KR101237652B1 - Resin coated metal sheet - Google Patents

Abstract

The resin coating metal plate of this invention is a resin coating metal plate provided with the resin film obtained from a surface treatment composition, Comprising: The surface treatment composition consists of the inorganic component which consists of several types of colloidal silica from which a surface area average particle diameter differs, and an olefin-alpha, It contains the resin component which consists of a (beta)-unsaturated carboxylic acid copolymer, the (alpha), (beta)-unsaturated carboxylic acid polymer, and an acrylic modified epoxy resin, and also contains a glycidoxy group containing silane coupling agent and metavanadate. By such a structure, the resin coating metal plate which combines not only corrosion resistance but also roll mold resistance and after-coating film coating adhesiveness is obtained.

Description

Resin-painted metal plate {RESIN COATED METAL SHEET}

The present invention relates to a resin-coated metal sheet excellent in roll formability and coating film adhesion after post-coating.

Examples of the hot dip galvanized steel sheet used for building materials include hot dip galvanized steel sheets (GI materials) in which pure zinc is plated on steel sheets, and alloyed hot dip galvanized steel sheets (GA materials) obtained by alloying them. The GI material is continuously passed through a plurality of sets of rolls arranged in a row (molding speed of about 20 to 70 m / min), and subsequently subjected to molding to form a molded article having a desired cross-sectional shape from a flat plate (roll forming). Afterwards, it is used as it is (deck), deck, or the like. In addition, the GA material is used for doors, shutters, and the like after the calcium lead rust preventive paint, the lead-free paint, or the electrodeposition paint is coated on the surface.

Background Art Conventionally, chromate treatment has been performed on surfaces of GI materials and GA materials for the purpose of improving corrosion resistance. However, due to the recent increase in environmental awareness, a treatment method (non-chromate treatment) that does not perform chromate treatment has been studied. Until now, a resin-coated metal sheet having a chromate-free resin film formed on a hot-dip galvanized steel sheet has been studied. Is being developed. For example, Japanese Patent Application Laid-Open No. 2009-61608 contains an inorganic component consisting of lithium silicate and colloidal silica, an olefin-α, β-unsaturated carboxylic acid copolymer, an α, β-unsaturated carboxylic acid polymer and an oxazoline group-containing copolymer. Disclosed is a resin coated metal plate comprising a resin film obtained from a surface treatment composition containing a resin component to be contained and further containing a glycidyl group-containing silane coupling agent and a metavanadate.

Although the resin film described in the above-mentioned document is suitably used for the GI material, excessive lateral pressure is applied to the GI material during roll molding, but the resin film described in the above-mentioned document has a specific gravity and can be thinned (about 2). This is because the roll damage to the resin film in roll molding can be reduced, and the resin film is hard to peel off (film debris) from the surface of the GI material by sliding with the roll. In roll forming, a coolant liquid is supplied to the surface of the GI material in order to ensure lubricity and to cool the processing heat, and the coolant liquid is repeatedly used. For example, a resin film (film residue) is used for GI. Even if peeled from the ash and incorporated into the coolant liquid, the resin film described in the above document has a large inorganic content and is precipitated in the coolant liquid due to its high specific gravity, so that the film residue floats in the coolant liquid and accompanies the coolant liquid. Because you can stop.

As a result, when the coolant liquid is wiped off from the surface of the GI material with the water pad (water cutting step), film residue is deposited on the water pad surface, and friction is generated between the deposited film residue and the molded product surface. It is possible to prevent the sound from being generated or the molded product can not exit the cut pad portion at a uniform running speed, resulting in a problem in the shape or dimensions of the product and deteriorating the yield.

On the other hand, when the said resin film is also applied to GA material, the coating film adhesiveness and corrosion resistance after post-coating may become inadequate. As a cause of insufficient coating film adhesion, the surface of the GA material has roughness and roughness, and the coating film adhesiveness is excellent due to the anchor effect. The resin film is buried with unevenness on the surface of the GA material or only the outermost surface of the GA material. It is thought that this is because the anchor effect of this covered GA material is lost. Further, as a cause of insufficient corrosion resistance, only the outermost surface of the GA material is covered by the resin film, and the bottom portion of the recess is exposed to zinc plating without forming a film. It is considered that corrosion occurs under the coating film. Furthermore, there existed a problem that a blister (swelling of a coating film) generate | occur | produces in the said corrosion resistance test around a crosscut part by the space | gap formed in the bottom of a recessed part, and the absorbent lithium silicate is used as a resin film component.

The present invention has been made in view of the above circumstances, and an object of the present invention is not only corrosion resistance, but also a chromate-free surface treatment composition which combines anti-roll moldability required in GI materials and coating film adhesion after post-painting required in GA materials. And the resin-coated metal plate provided with the resin film obtained from this surface treatment composition.

The resin coating metal plate of this invention which could solve the said subject is a resin coating metal plate provided with the resin film obtained from a surface treatment composition, Comprising: The said surface treatment composition is the inorganic body which consists of several types of colloidal silica from which a surface area average particle diameter differs. And 60 to 80 parts by mass of the component, and 20 to 40 parts by mass of the resin component composed of an olefin-α, β-unsaturated carboxylic acid copolymer, an α, β-unsaturated carboxylic acid polymer and an acrylic modified epoxy resin. 5-15 mass parts of glycidoxy group containing silane coupling agents, and 0.5-3 mass parts of metavanadate salts are further contained with respect to a total of 100 mass parts of the said resin component.

In the present invention, the inorganic component comprises colloidal silica (A) having a surface area average particle diameter of 4 to 6 nm and colloidal silica (B) having a surface area average particle diameter of 10 to 20 nm, wherein the (A) and (B) It is a preferred embodiment that the mixing ratio is 70:30 to 40:60 (mass ratio).

In addition, in this specification, the colloidal silica whose surface area average particle diameter is 4-6 nm means the colloidal silica in which colloidal silica of surface area particle diameter 5 nm occupies 90% (preferably 95%) or more. In addition, colloidal silica whose surface area average particle diameter is 10-20 nm means colloidal silica in which colloidal silica with a surface area particle diameter of 12 nm occupies 90% (preferably 95%) or more. The surface area average particle diameter can generally be measured by the Sears method or the BET method. In order to more accurately measure the surface area average particle diameter, an electron microscope capable of directly measuring the particle diameter is effective.

Moreover, it is also a preferable embodiment that the said resin component contains 2-15 mass% of said acrylic modified epoxy resins.

Further, the surface tension of the surface treatment composition is 50 dyn / cm or less, the adhesion amount of the resin film is 0.2 to 1 g / m ² in dry mass, or the metal plate provided with the resin film is hot-dip galvanized steel sheet or alloy melting Galvanized steel is also a preferred embodiment.

Since the resin coating metal plate of this invention is equipped with the resin film obtained from the predetermined surface treatment composition, it can satisfy not only corrosion resistance but the roll moldability required by GI material, and the coating film adhesiveness after post-coating required by GA material.

The resin coating metal plate of this invention is a resin coating metal plate provided with the resin film obtained from a surface treatment composition, 60-80 mass parts of inorganic components with which the said surface treatment composition consists of plural types of colloidal silica from which a surface area average particle diameter differs. And 20 to 40 parts by mass of a resin component composed of an olefin-α, β-unsaturated carboxylic acid copolymer, an α, β-unsaturated carboxylic acid polymer and an acrylic modified epoxy resin, and a total of 100 of the inorganic component and the resin component. It is characterized by further containing 5-15 mass parts of glycidoxy group containing silane coupling agents with respect to mass parts, and 0.5-3 mass parts of metavanadate. EMBODIMENT OF THE INVENTION Hereinafter, the resin coating metal plate of this invention is demonstrated in detail.

On the other hand, the coating of the present invention contains considerably more inorganic components than the resin component. However, the term "resin coating" is also used in the present invention because it is often called "resin coating."

(Inorganic ingredient)

In the present invention, lithium silicate is not used as the inorganic component. By not using lithium silicate, which exhibits water absorption, the surface of the resin-coated metal plate is subjected to post-coating and crosscutting, and thus, the adhesion of the coating film is inhibited from being deteriorated even if excessive corrosion resistance tests such as saline immersion test and salt spray test are performed. can do.

<Colloidal silica>

One of the features of the present invention is the use of a plurality of colloidal silicas having different surface area average particle diameters as inorganic components. Thereby, the affinity (familiarity) of binder resin (resin component) and colloidal silica improves, and the film-forming property (cohesion force of colloidal silica particles) of the resin film formed is improved, and a dense film Can be formed.

More specifically, the inorganic component preferably comprises colloidal silica (A) having a surface area average particle diameter of 4 to 6 nm and colloidal silica (B) having a surface area average particle diameter of 10 to 20 nm. It is more preferable to consist of (A) and colloidal silica (B).

Colloidal silica is believed to improve the corrosion resistance of the metal plate by inhibiting dissolution / elution of the metal plate by the buffering effect of pH or the formation of the passivation film by dissolving and eluting at the coating defects in a corrosive environment. In order to fully exhibit these effects, it is effective to use colloidal silica (A). On the other hand, since the surface activity of the colloidal silica (A) is high, when the colloidal silica (A) alone is used, the liquid stability of the surface treatment composition may deteriorate with time (increase in viscosity at about 48 hours) or a dense film There was a problem that it could not be formed, and the specific gravity of the resin film could not be increased by increasing the content rate of the inorganic component in the resin film. And the present inventors earnestly examined and, when using together colloidal silica (B) of 10-20 nm of surface area average particle diameters with small surface activity, it can raise the content rate of an inorganic component, without reducing the liquid stability of a surface treatment composition. Found that there is. In addition, the surface area average particle diameter of the colloidal silica in this specification is a value measured by the Sears method when the surface area average particle diameter is about 1-10 nm, the value measured by the BET method when it is about 10-100 nm, or a manufacturer's It means the notarized value described in the pamphlet.

The mixing ratio of colloidal silica (A) and colloidal silica (B) is preferably 70:30 to 40:60, more preferably 65:35 to 45:55 by mass ratio. When the mass ratio of colloidal silica (A) exceeds 70, affinity with a resin component may worsen, the liquid stability of a surface treatment composition may deteriorate, and uniform and dense film formation may not be possible. Thereby, the corrosion resistance of the resin-coated metal plate and the coating film adhesiveness after post-coating deteriorate. When the mass ratio of colloidal silica (A) is less than 40, there is a possibility that the amount of Si ions dissolved and eluted in the coating defect portion in a corrosive environment decreases and the corrosion resistance is deteriorated.

Colloidal silica is commercially available, and "Snowtex (registered trademark) XS" by Nissan Chemical Industries is mentioned as a thing of surface area average particle diameter 4-6 nm, for example. In addition, as a thing of 10-20 nm of surface area average particle diameters, "Snowtex (trademark) 40", "Snowtex (trademark) N" by Nissan Chemical Industries, "Snowtex (trademark) SS", "Snow" Tex (trademark) O ", the" adelite (trademark) AT-30 "by ADEKA company, the" adelite (trademark) AT-30A ", etc. are mentioned. When the surface treatment composition used for forming the resin film is water-based, it is preferable to select the type of colloidal silica in accordance with the pH of the surface treatment composition in order to disperse the colloidal silica well.

The inorganic component comprised of the said colloidal silica shall be 60-80 mass parts in 100 mass parts in total with the resin component mentioned later. Since the film forming property of the resin film formed is favorable for the surface treatment composition in which the amount of an inorganic component is in the said range, film peeling hardly arises and the roll moldability of a resin coating metal plate improves. In addition, the surface tension of the surface treatment composition is lowered (preferably 50 dyn / cm or less), so that the surface treatment composition penetrates the surface (concave portion) of the GA material having rough surface roughness and inferior water wettability, and thus along the concave surface of the GA material. Since a resin film is formed, corrosion resistance and coating film adhesiveness also improve.

When the amount of the inorganic component exceeds 80 parts by mass, the resin component is insufficient, so that the film forming property of the formed film is insufficient and a normal film cannot be formed. As a result, the barrier effect in a corrosive environment may also fall, and corrosion resistance may deteriorate. In addition, the film becomes excessively hard and brittle, cracks occur, and film peeling easily occurs during roll forming. Furthermore, since colloidal silica (dispersing amorphous silica particles in water to form a colloidal shape) has a high surface tension (about 66 to 73 dyn / cm), when the amount of inorganic components exceeds 80 parts by mass, the surface tension of the surface treatment composition is increased. It becomes large, wettability with the metal plate in which a resin film is formed also worsens, and uniform formation of a thin film film may become difficult. In particular, since it becomes difficult to form a uniform and ultra-thin film on the uneven portion of the surface of the GA material, coating film adhesion and corrosion resistance decrease.

When the quantity of an inorganic component is less than 60 mass parts, the corrosion resistance of the resin coating metal plate obtained may become inadequate. In addition, since the hardness of the film is insufficient, the specific gravity of the film does not increase so much that the thin film of the resin film becomes difficult, and the film peeling easily occurs during roll forming. Furthermore, due to the fact that the specific gravity of the resin film does not increase, it is not possible to settle the film residue in the coolant liquid water tank, and the effect of suppressing the deposition on the surface of the water pad is insufficient. It may deteriorate a product shape. Moreover, when a resin film is formed in a metal plate (especially GA material) using the surface treatment composition whose quantity of an inorganic component is less than 60 mass parts, the content rate of a resin component increases and film forming property improves, but Si ion elution amount which suppresses corrosion is carried out. Because of this decrease, corrosion (corrosion under the coating) progresses between the resin film and the surface of the metal plate (plating layer interface), and as a result, the coating film adhesion after the post-coating deteriorates, or in the corrosion test after the post-coating, It may occur.

In this invention, it is more preferable that an inorganic component is 65-75 mass parts in 100 mass parts of total of an inorganic component and a resin component. In that case, it is preferable that the mixing ratio of colloidal silica (A) and (B) shall be 50:50 (mass ratio), and the corrosion resistance and coating-film adhesiveness of GA material can be made especially favorable.

(Resin ingredient)

In addition to the said inorganic component, the surface treatment composition used by this invention is an olefin- (alpha), (beta)-unsaturated carboxylic acid copolymer (henceforth a "olefin-acid copolymer" may be called), and (alpha), (beta)-unsaturated carboxylic acid polymer (henceforth). It may be called "carboxylic acid polymer", and the resin component comprised from acrylic modified epoxy resin.

By forming a resin film from the surface treatment composition containing both an olefin-acid copolymer and a carboxylic acid polymer, the corrosion resistance of the resin coating metal plate obtained improves. Although the exact mechanism is not clear, it is presumed that the use of both forms a dense resin film, which effectively suppresses the permeation of water and oxygen.

In addition, the "olefin-acid copolymer" in this invention is a copolymer of an olefin and the (alpha), (beta)-unsaturated carboxylic acid, and the structural unit derived from an olefin is 50 mass% or more (namely, (alpha), (beta)-unsaturated) in a copolymer. It means that the structural unit derived from carboxylic acid is 50 mass% or less). In addition, a "carboxylic acid polymer" is a polymer obtained by using an (alpha), (beta)-unsaturated carboxylic acid as a monomer, and means that the structural unit derived from (alpha), (beta)-unsaturated carboxylic acid is 90 mass% or more in a polymer. In addition, "(alpha), (beta)-unsaturated carboxylic acid" also includes "(alpha), (beta)-unsaturated carboxylic acid salt which neutralized a part of carboxyl group with the neutralizing agent mentioned later.

<Olefin-acid copolymer>

The olefin-acid copolymer used in the present invention can be produced by copolymerizing olefins with an α, β-unsaturated carboxylic acid by a known method, and is also commercially available. In the present invention, one or more olefin-acid copolymers may be used.

Although there is no limitation in particular in the olefin which can be used for manufacture of an olefin acid copolymer, ethylene, propylene, etc. are preferable and ethylene is more preferable. As the olefin-acid copolymer, any of olefin constituent units derived only from one olefin or from two or more olefins can be used.

The alpha, beta -unsaturated carboxylic acid that can be used in the production of the olefin-acid copolymer is not particularly limited, but examples thereof include monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid and isocrotonic acid; And dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid. Among these, acrylic acid is preferable. As the olefin-acid copolymer, any of the constituent units of the α, β-unsaturated carboxylic acid may be derived from only one α, β-unsaturated carboxylic acid or from two or more α, β-unsaturated carboxylic acids.

The olefin-acid copolymer used in the present invention may have a structural unit derived from other monomers within a range that does not adversely affect the corrosion resistance and the like which is the effect of the present invention. Among the olefin-acid copolymers, the structural unit amount derived from other monomers is preferably 10% by mass or less, more preferably 5% by mass or less, and most preferred olefin-acid copolymers are olefins and α, β-unsaturated carboxylic acids. It consists of only. Ethylene-acrylic acid copolymer is mentioned as a preferable olefin-acid copolymer.

The α, β-unsaturated carboxylic acid in the olefin-acid copolymer is used to improve the adhesion between the resin film and the metal plate, and the amount of the α, β-unsaturated carboxylic acid in the copolymer is preferably 5% by mass or more, more preferably 10 mass% or more. However, since there exists a possibility that corrosion resistance may fall when alpha, (beta)-unsaturated carboxylic acid becomes excess, the amount of (alpha), (beta)-unsaturated carboxylic acid in a copolymer becomes like this. Preferably it is 30 mass% or less, More preferably, it is 25 mass% or less.

The mass average molecular weight (Mw) of the olefin-acid copolymer used in the present invention is preferably 1,000 to 100,000, more preferably 3,000 to 70,000, and even more preferably 5,000 to 30,000 in terms of polystyrene. This Mw can be measured by GPC using polystyrene as a standard.

<Carboxylic acid polymer>

As a carboxylic acid polymer used by this invention, the homopolymer or copolymer of 1 type, or 2 or more types of (alpha), (beta)-unsaturated carboxylic acid, or the copolymer which copolymerized another monomer further is mentioned. Such carboxylic acid polymers can be produced by a known method and are also commercially available. In the present invention, one kind or two or more kinds of carboxylic acid polymers can be used.

As the α, β-unsaturated carboxylic acid that can be used in the preparation of the carboxylic acid polymer, all of the α, β-unsaturated carboxylic acids exemplified as those that can be used in the synthesis of the olefin-acid copolymer can be used. Among these, acrylic acid and maleic acid are preferable, and maleic acid is more preferable.

The carboxylic acid polymer may contain a structural unit derived from monomers other than the α, β-unsaturated carboxylic acid, but the amount of the structural unit derived from other monomers is 10% by mass or less, preferably 5% by mass or less in the polymer, The carboxylic acid polymer which consists only of (beta)-unsaturated carboxylic acid is more preferable.

Examples of the preferred carboxylic acid polymer include polyacrylic acid, polymethacrylic acid, acrylic acid-maleic acid copolymer, polymaleic acid, and the like, and polymaleic acid is more preferable from the viewpoint of coating film adhesion, resin film adhesion, and corrosion resistance. By using polymaleic acid, the particle diameter of the resin emulsion produced becomes small (20-60 nm), and the film obtained by making into a film becomes dense, and corrosion resistance etc. improve. In addition, since the amount of carboxyl groups is large, the adhesion between the resin film and the metal plate is improved, whereby the corrosion resistance is further improved.

Mw of the carboxylic acid polymer used in the present invention is preferably 500 to 30,000, more preferably 800 to 10,000, still more preferably 900 to 3,000, and most preferably 1,000 to 2,000 in terms of polystyrene. This Mw can be measured by GPC using polystyrene as a standard.

The content ratio of the olefin-acid copolymer and the carboxylic acid polymer in the surface treatment composition is 1,000: 1 to 10: 1, preferably 200: 1 to 20: 1, more preferably 100: 1 to 100: 3. When the content ratio of the carboxylic acid polymer is too low, the effect of combining the olefin-acid copolymer and the carboxylic acid polymer is not sufficiently exhibited. On the contrary, when the content ratio of the carboxylic acid polymer is excessive, the olefin-acid copolymer and the carboxylic acid polymer in the surface treatment composition. There is a fear that a uniform resin film is not formed by phase separation.

<Acrylic modified epoxy resin>

The resin component also includes an acrylic modified epoxy resin. Conventionally, a block isocyanate (thermal crosslinking agent) is present in a film as a resin component as a method of improving the coating film adhesiveness of a thick coating, and it uses the heat of baking after baking (baking temperature) of a block isocyanate. BACKGROUND ART A technique is known in which a blocking agent is dissociated to regenerate an active isocyanate group to cure and crosslink the coating film and the coating film. However, the calcium lead acid rust-preventive paint used in the field of building materials as a coating material for post-painting is a mainstream type that does not require heat baking (drying), and thus cannot use the above technique.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining the said problem, it discovered that the coating film adhesiveness of a resin film improves by using together the acrylic modified epoxy resin which can be formed at low temperature as a resin component. Although the exact mechanism by which an acrylic modified epoxy resin is used together improves coating film adhesiveness is unclear, the acrylic modified epoxy resin does not function as a binder of an inorganic component (colloidal silica), but is deposited on the outermost surface of the resin film in a patterned form (striped in a stripe shape). By doing so, it does not contribute to the improvement of corrosion resistance but is estimated to contribute to the improvement of the coating-film adhesiveness after post-coating. The reason why the acrylic modified epoxy resin is formed on the outermost surface of the resin film is that the emulsion particle diameter of the olefin-acid copolymer or the carboxylic acid polymer is 20 to 60 nm, whereas the emulsion particle diameter of the acrylic modified epoxy resin is about 100 nm or more. do.

The acrylic modified epoxy resin used in the present invention copolymerizes a polymerizable unsaturated group-containing epoxy resin obtained by reacting an epoxy resin with an unsaturated fatty acid and (meth) acrylic acid, or reacts an epoxy resin with a glycidyl group-containing vinyl monomer and an amine. It can manufacture by copolymerizing the polymerizable unsaturated group containing epoxy resin obtained by making it and (meth) acrylic acid.

In particular, an aqueous acrylic modified epoxy resin is commercially available, for example, "MODEPIX (registered trademark) 301", "MODEPIX (registered trademark) 302", "MODEPIX (registered trademark) 303" made by Arakawa Chemical Industries, Ltd., "Mode" Fix (trademark) 304 "etc. are mentioned. The acrylic modified epoxy resins may be used alone or in combination of two or more thereof.

It is preferable that 2 mass% or more (more preferably 3 mass% or more) is contained in 100 mass% of resin components, and the acrylic modified epoxy resin contains 15 mass% or less (more preferably 7 mass% or less). desirable. Within the said range, the coating film adhesiveness after post-coating can be improved, without impairing roll moldability and corrosion resistance of a resin coating metal plate.

When the content rate of acrylic modified epoxy resin is less than 2 mass%, the coating-film adhesive improvement effect after post-coating is not recognized. Moreover, when the content rate of acrylic modified epoxy resin exceeds 15 mass%, there exists a tendency for corrosion resistance to fall. In particular, in a GA material, coating film adhesiveness deteriorates significantly and blister may generate | occur | produce at the same time. When the content of the acrylic modified epoxy resin exceeds 15% by mass, the precise mechanism by which the corrosion resistance and the coating film adhesion after the lowering of the corrosion resistance is lowered is not clear, but the presence of the acrylic modified epoxy resin in excess results in the presence of an olefin-acid mixture. It is presumably because it inhibited the film formation of the copolymer and the carboxylic acid polymer emulsion.

<Glycidoxy group-containing silane coupling agent>

The surface treatment composition of this invention contains the glycidoxy group containing silane coupling agent (more specifically, the silane coupling agent which has the glycidoxy group at the terminal). When the glycidoxy group-containing silane coupling agent is used, the adhesion between the metal plate and the resin film is improved. Moreover, it is thought that it also has the effect of improving the bonding force of the inorganic component and resin component in a resin film, and the effect of improving roll moldability and corrosion resistance is large. Furthermore, when the glycidoxy group-containing silane coupling agent is added, the surface tension of the surface treatment composition is lowered, so that the wettability with the metal plate is improved, and the coating property of the surface treatment composition is improved, so that a uniform resin film can be formed. do. In addition, when the surface treatment composition is circulated and used in a spray wringer method (application method in which the surface treatment composition is sprayed on the surface of the metal plate and then clamped with a ringer roll), the effect of inhibiting foaming due to the surfactant in the composition is suppressed. To be uttered.

Examples of the glycidoxy group-containing silane coupling agent include γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403), and γ-glycidoxymethyl Dimethoxysilane, and the like.

The amount of glycidoxy group-containing silane coupling agent in the surface treatment composition is 5 parts by mass or more, preferably 7 parts by mass or more, 15 parts by mass or less, preferably 13 parts by mass based on 100 parts by mass of the total of the inorganic component and the resin component. Or less. When the amount of the silane coupling agent is less than 5 parts by mass, the effect of improving the adhesion between the metal plate and the resin film is not recognized. Moreover, the binding force of the inorganic component and resin component in a resin film component may fall, film hardness may fall or film density may worsen, and roll moldability, coating film adhesiveness, and corrosion resistance may fall. Even if the amount of the glycidoxy group-containing silane coupling agent exceeds 15 parts by mass, the effect of improving the adhesion between the metal plate and the resin film and the effect of improving the bonding strength between the inorganic component and the resin component in the resin coating component reach a limit, which causes a cost increase. On the contrary, roll formability, coating-film adhesiveness, and corrosion resistance may fall, or liquid stability of a surface treatment composition may fall, and gelatinization and precipitation of colloidal silica may be caused.

<Metavanadate>

The surface treatment composition of the present invention further includes metavanadate. Metavanadate also elutes like colloidal silica, thereby suppressing dissolution and elution of the metal plate, thereby improving corrosion resistance. Metavanadate has an effect of improving the corrosion resistance, particularly with respect to GA materials. In order to exhibit this effect effectively, 0.5-3 mass parts of metavanadate may be used with respect to a total of 100 mass parts of an inorganic component and a resin component. When less than 0.5 mass part, the effect of improving corrosion resistance will become insufficient. Moreover, when it adds exceeding 3 mass parts, the tendency for corrosion resistance to fall slightly is recognized. This is presumably because excess metavanadate inhibits the hydrolysis reaction of the glycidoxy group-containing silane coupling agent and slightly affects the binding force between the inorganic component and the resin component. Furthermore, there exists a tendency for coating film adhesiveness to fall remarkably and liquid stability of a surface treatment composition also deteriorates. The amount of metavanadate is more preferably 0.7 to 1.5 parts by mass. In addition, the suitable amount of this metavanadate is V element conversion amount.

Examples of metavanadate include sodium metavanadate (NaVO ₃ ), ammonium metavanadate (NH ₄ VO ₃ ), potassium metavanadate (KVO ₃ ), and the like. These may be used independently and may be used in combination of 2 or more type. These metavanadates are commercially available and can be obtained easily.

<Other Ingredients>

The surface treatment composition of this invention may further contain the carbodiimide group containing compound. Carbodiimide groups can react with carboxyl groups in olefin-acid copolymers and carboxylic acid polymers to reduce the amount of carboxyl groups in the resin coating to improve alkali resistance. In the present invention, one or two or more carbodiimide group-containing compounds can be used.

Carbodiimide group-containing compounds are isocyanates such as hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (HXDI), 4, 4-diphenylmethane diisocyanate (MDI) or tolylene diisocyanate (TDI) and the like can be prepared by heating in the presence of a carbodiimidation catalyst, and further modified by aqueous (water-soluble, It may be made to be water-soluble or water-dispersible. When the surface treatment composition is water-based, an aqueous carbodiimide group-containing compound is preferable. Moreover, the compound containing a some carbodiimide group in 1 molecule is preferable. If it has several carbodiimide groups in 1 molecule, corrosion resistance etc. can be improved further by the crosslinking reaction with the carboxyl group in a resin component.

Examples of commercially available carbodiimide group-containing compounds include N, N-dicyclohexylcarbodiimide, N, N-diisopropylcarbodiimide and the like, and polycarbodiimide manufactured by Nisshinbo Corporation (plural carboimides in one molecule). The "carbodilite (trademark)" series which are the polymer which has a diimide group) are mentioned. As a grade of "Carbodiite (registered trademark)", water-soluble "SV-02", "V-02", "V-02-L2", "V-04" and the emulsion type "E-01", "E-02", and the like.

Carbodiimide group containing compound amount is set according to the quantity of the olefin acid copolymer and carboxylic acid polymer which are a crosslinking partner. That is, it is preferably 0.1 mass part or more, More preferably, it is 0.5 mass part or more, More preferably, it is 8 mass parts or more with respect to a total of 100 mass parts of an olefin acid copolymer and a carboxylic acid polymer. On the other hand, when the amount of carbodiimide group-containing compound is excessive, the combined effect of the olefin-acid copolymer and the carboxylic acid polymer is reduced. In addition, excessive use of the aqueous carbodiimide group-containing compound in the aqueous surface treatment composition may adversely affect water resistance and corrosion resistance. From this viewpoint, the carbodiimide group-containing compound amount is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 16 parts by mass or less with respect to 100 parts by mass.

The surface treatment composition of the present invention is a wax, a crosslinking agent, a diluent, an anti-skinning agent, a surfactant, an emulsifier, a dispersant, a leveling agent, an antifoaming agent, a penetrating agent, a film forming agent, a dye, a pigment, within a range that does not impair the effect of the present invention. Thickeners, lubricants, and the like may be contained.

<Surface Tension of Surface Treatment Composition>

In the surface treatment composition used in the present invention, it is preferable to lower the surface tension of the surface treatment composition by appropriately adjusting the blending ratio of the inorganic component and the resin component (specifically, the inorganic component: resin component = 60:40 to 80:20). Specifically, it is 50 dyn / cm or less, More preferably, it is 48 dyn / cm or less. Thereby, a surface treatment composition may invade the surface (concave part) of GA material which is rough in surface roughness and is inferior in water wettability, and can improve the corrosion resistance and coating-film adhesiveness of GA material. In addition, the method of measuring the surface tension of a surface treatment composition is mentioned later.

As mentioned above, although the surface treatment composition used by this invention was demonstrated in detail, the manufacturing method of a surface treatment composition is demonstrated below.

<Method for Producing Surface Treatment Composition>

The surface treatment composition of the present invention may be any of a solvent-based composition or an aqueous composition which can be applied to the surface of a metal plate, but is preferably an aqueous composition due to environmental problems. The surface treatment composition contains an organic solvent (in the case of a solvent-based composition) or water, preferably deionized water (in the case of an aqueous composition), colloidal silica, an olefin-acid copolymer, a carboxylic acid polymer, an acrylic modified epoxy resin, and a glycidoxy group. A silane coupling agent, metavanadate, a carbodiimide group containing compound, or another component can be prepared by mix | blending and stirring a predetermined amount as needed.

When preparing the surface treatment composition, a part of the glycidoxy group-containing silane coupling agent and the carbodiimide group-containing compound are added to an emulsion (emulsion) of the olefin-acid copolymer and the carboxylic acid polymer to prepare a mixture thereof. It is preferable to add colloidal silica (preferably in order from small surface area average particle diameter in order), remaining glycidoxy group containing silane coupling agent, metavanadate, and acrylic modified epoxy resin in this order. Do. If metavanadate is added before the glycidoxy group-containing silane coupling agent, the hydrolysis reaction of the silane coupling agent may be suppressed, thereby inhibiting the effect of the silane coupling agent. In addition, the glycidoxy group-containing silane coupling agent is preferably added in two portions as described above. The silane coupling agent added first contributes to the refinement of the emulsion particles and consequently contributes to improving the corrosion resistance by densifying the resin film, and the silane coupling agent added later contributes to securing adhesion to the metal plate and improving the film properties. Because. On the other hand, as for the quantity of the silane coupling agent added first, 0.1 mass part or more (more preferably 2 mass parts or more) is preferable with respect to a total of 100 mass parts of an olefin acid copolymer and a carboxylic acid polymer, and 10 mass parts or less (more Preferably 7 mass parts or less) is preferable. In addition, the quantity of the silane coupling agent added later is as above-mentioned.

When stirring the said component, you may heat. It is preferable to heat especially when emulsifying an olefin acid copolymer in the presence of a carboxylic acid polymer.

When manufacturing an aqueous surface treatment composition, it is preferable to emulsify the olefin-acid copolymer which is a main component of a resin component. The olefin-acid copolymer can be emulsified using an emulsifier or by neutralizing the carboxyl groups in the copolymer. If an emulsifier is used, the average particle diameter of the aqueous emulsion of an olefin acid copolymer can be made small, and the film formability, thereby, the density of a resin film, etc. can be improved.

However, it is more preferable to neutralize and emulsify the carboxyl group in the olefin-acid copolymer. This is because the amount of emulsifier can be reduced by neutralizing and emulsifying the carboxyl group, or it can be completed without using an emulsifier, and the adverse effect of the emulsifier on the water resistance and corrosion resistance of the resin film can be reduced or eliminated. When neutralizing the carboxyl group in the olefin-acid copolymer, it is preferable to use about 0.5 to 0.95 equivalents, more preferably about 0.6 to 0.8 equivalents of base relative to the carboxyl group. If the degree of neutralization is too small, the emulsification property is not so improved. On the other hand, if the degree of neutralization is too large, the viscosity of the composition containing the olefin-acid copolymer may be too high.

As a base for neutralization, for example, strong bases composed of a group consisting of hydroxides of alkali metals and alkaline earth metals (such as NaOH, KOH, Ca (OH) ₂ , preferably NaOH), aqueous ammonia, primary and secondary And tertiary amines (preferably triethylamine). If strong bases, such as NaOH, are used, emulsification may be improved. However, when the amount is too large, the corrosion resistance of the resin film may be lowered. On the other hand, an amine having a low boiling point (preferably an amine having a boiling point of 100 ° C. or lower at atmospheric pressure; for example, triethylamine) does not significantly reduce the corrosion resistance of the resin film. As a reason for this, the low boiling point amine volatilizes, etc. can be considered when apply | coating a surface treatment composition, and carrying out heat drying to form a resin film. However, since an amine has a small emulsification improvement effect, it is preferable to neutralize combining the strong base and an amine. The best combination is a combination of NaOH and triethylamine. When using in combination with a strong base and an amine, it is preferable to use about 0.01-0.3 equivalents of strong bases, and about 0.4-0.8 equivalents with respect to the carboxyl group amount of an olefin acid copolymer.

When using an aqueous surface treatment composition, you may mix | blend a small amount of organic solvents in order to reduce interfacial tension and to improve wettability to a metal plate. Examples of the organic solvent for this purpose include methanol, ethanol, isopropanol, butanol, hexanol, 2-ethylhexanol, ethylene glycol ethyl ether, ethylene glycol butyl ether, diethylene glycol, propylene glycol and the like.

<Solid content of surface treatment composition>

Solid content of the surface treatment composition used by this invention does not have limitation in particular, What is necessary is just to adjust according to the coating method of the surface treatment composition to a metal plate. Solid content of a surface treatment composition is generally about 5-20 mass%, For example, when apply | coating by the spray ringer method (the coating method which sprays a surface treatment composition to the surface of a metal plate, and then clamps with a ringer roll), it is 10-18 mass%. The degree is suitable.

<Formation method of resin film>

In the present invention, the method and conditions for forming the resin film on the metal plate are not particularly limited, and the resin coating metal plate is produced by applying the surface treatment composition to one or both surfaces of the metal plate surface by a known coating method and drying it by heating. can do. As a coating method of a surface treatment composition, the bar coater method, the curtain flow coater method, the roll coater method, the spray method, the spray ringer method, etc. are mentioned, Among these, the bar coater method and the spray ringer method are preferable from a cost viewpoint. Do. Moreover, there is no restriction | limiting in particular also in heat drying conditions, About 50-120 degreeC, Preferably about 70-100 degreeC can be illustrated as heat drying temperature. Too high a heat drying temperature is not preferable because the resin film deteriorates.

<Amount of Resin Coating>

The adhesion amount of the resin film in the resin coating metal plate is preferably a dry mass of 0.2 to 1 g / m ² , more preferably 0.3 to 0.7 g / m ² . When the adhesion amount is less than 0.2 g / m ² , it is difficult to cover the metal plate surface, which greatly impairs roll formability, coating film adhesion, and corrosion resistance. On the other hand, when adhesion amount exceeds 1 g / m < ² >, corrosion resistance becomes favorable, but since the amount of film peeling off at the time of roll forming increases, there exists a possibility that the amount of film residue deposited on a water pad may increase, and it may cause trouble. . Moreover, coating film adhesiveness is largely impaired. On the other hand, the resin film of this invention contains many inorganic components, and its specific gravity is large. For this reason, it is succeeded in thinning even if the amount of adhesion is the same compared with the conventional resin film rich in the resin component. This also contributes to the reduction of film dregs.

<Metal plate>

The metal sheet used in the present invention is not particularly limited, and examples thereof include an unplated cold rolled steel sheet, a hot dip galvanized steel sheet (GI), an alloyed hot dip galvanized steel sheet (GA), an electrogalvanized steel sheet (EG), an aluminum plate and a titanium plate. Can be mentioned. Among these, it is preferable to apply this invention to the hot-dip galvanized steel plate (GI) and alloyed hot-dip galvanized steel plate GA which are not subjected to chromate treatment.

Example

Hereinafter, the present invention will be described in detail based on examples. However, the following Examples do not limit the present invention, and all modifications are made within the technical scope of the present invention without departing from the gist of the preceding and later stages.

First, the evaluation method used by the experiment example is demonstrated below.

(Roll resistance)

A 4.0 mm x 300 mm sample was cut out from the resin-coated metal sheet, set vertically to a tensile testing machine, and a flat die (material: SKD11) was abutted on the sample back surface. Subsequently, a jig (semi-cylindrical die, material: SKD11) having a convex portion having a tip radius R of 9.1 mm is abutted on the opposite surface (front face) of the sample abutting the flat die, and a load of 4900 N (500 kgf) is applied to the jig. The jig was pulled downward at 300 mm / min while walking in the horizontal direction within the range where the flat die abuts on the sample back surface. Thereafter, the semi-cylindrical die was removed from the sample and returned to the position before the sliding motion, and the sliding motion similar to the above was repeated 9 times (10 times in total). Subsequently, the coating amount of the portion W ₁ and the non-slip portion W _{0 in} which the semi-cylindrical dies were repeatedly slid was analyzed by a fluorescent X-ray analyzer, and the film residual ratio was calculated from the following equation (1). It evaluated by the following reference | standard.

◎: 95% or more of film remaining rate

○: 90% or more of film residual rate is less than 95%

(Triangle | delta): 80% or more of film residual ratio is less than 90%

×: less than 80%

In addition, the coating amount of the coating was analyzed from the Si element of the colloidal silica (SiO ₂ ) contained in the coating and calculated from the ratio of the Si element included in the coating based on the following equation (2).

C: ratio of colloidal silica (SiO ₂ ) in the coating

(Corrosion resistance (SST reputation))

Based on JIS Z2371, the salt-coating test was performed to the resin coating metal plate, and time until white blue incidence rate (the total area of 100x blue rust generate | occur | produced / resin coating metal plate) became 5%. On the other hand, corrosion resistance in building materials is not practically a problem if both GI and GA materials are less than 5% of white rust generated at 48 hours of normal SST elapsed after chromate treatment. Moreover, also in other uses, if it is 96 hours or more in GI material and 72 hours or more in GA material, there is no problem.

(Corrosion Resistance (Reputation) in JASO Cycle Test)

JASO cycle test was done based on JISH8502. One cycle is salt spray (temperature 35 ° C × 2 hours) → drying (temperature 35 ° C × humidity 30% or less × 4 hours) → wetting (temperature 50 ° C × humidity 95% or more × 2 hours) (each includes transition time) do). After 20 cycles, the white rust incidence rate (the total area of 100 × white rust generated / the total area of the resin coated metal sheet) was evaluated based on the following criteria.

◎: less than 5% of white rust incidence

○: white rust incidence 5% or more but less than 10%

△: white rust incidence 10% or more but less than 20%

×: 20% or more occurrence of white rust

(Surface tension)

According to JIS K2241, a 23% aqueous solution of the surface treatment composition was prepared using ion-exchanged water, and the surface tension of the aqueous solution was measured using a surface tension measuring device (manufactured by Shimadzu Corporation) and a metal ring as a probe under room temperature conditions. Saved by.

(Film adhesion)

First, dilute the calcium lead acid rust preventive paint (Nippon Paint Co., Ltd., Hellgon CP Light Gray) with thinner (Nippon Paint Co., Ltd., paint thinner A) to adjust the viscosity (20 seconds with Pod Cup # 4). After spray-coating on the resin coating metal plate by spray pressure 39N (4 kgf), and aging for 12 hours, it dried for 60 minutes at the temperature of 80 degreeC, and produced the coating material of 35-40 micrometers of coating film thicknesses.

<Salt spray test>

Subsequently, after sealing to the back edge of a coating material, a crosscut was put with a cutter knife, the salt spray test (SST) was performed according to JIS Z2371, and after a lapse of 360 hours, one largest swelling width from the crosscut portion. Was measured and evaluated based on the following criteria.

◎: less than 1.0 mm swelling width

○: swelling width 1.0 mm or more less than 1.5 mm

△: swelling width 1.5 mm or more less than 2.0 mm

×: swelling width 2.0 mm or more

<Saline Immersion Test>

After sealing to the back edge of the coating material, the crosscut was put with a cutter knife, immersed in an aqueous sodium chloride solution (30 g / L) at a liquid temperature of 23 ° C. ± 2 ° C. for 96 hours, washed with water, and then wiped off the surface moisture immediately. The tape peeling test of the crosscut part was performed. About the coating material after peeling test, one largest peeling width from a crosscut part was measured, and the following reference | standard evaluated.

◎: less than 1.0 mm peeling width

○: 1.0 mm or more peeling width less than 1.5 mm

△: peeling width 1.5 mm or more less than 2.0 mm

X: Peeling width 2.0 mm or more

(Preparation of emulsion (emulsion) of olefin-acid copolymer and carboxylic acid polymer)

Ethylene-acrylic acid copolymer (manufactured by Dow Chemical Co., Ltd., Polymer Cole (registered trademark) 5990I, acrylic acid) in an autoclave having an emulsification facility equipped with a stirrer, a thermometer, and a temperature controller: 20 mass% , Mass average molecular weight (Mw): 20,000, melt index: 1300, acid value: 150) 200.0 parts by mass, a polymaleic acid aqueous solution ("Nonpole (registered trademark) PMA-50W" manufactured by Nichi Corporation), Mw: about 1100 ( Polystyrene conversion), 50% by mass product) 8.0 parts by mass, 35.5 parts by mass of triethylamine (0.63 equivalents to carboxyl group of ethylene-acrylic acid copolymer), 6.9 parts by mass of 48% NaOH aqueous solution (with respect to carboxyl group of ethylene-acrylic acid copolymer) 0.15 equivalents), tall oil fatty acid (manufactured by Harima Chemicals Co., Ltd., Hatol FA3), 3.5 parts by mass, and ion exchanged water 792.6 parts by mass were added and sealed, and the mixture was cooled to 30 ° C after stirring at 150 ° C and 5 atmospheres for 3 hours. Next, 10.4 parts by mass of a glycidoxy group-containing silane coupling agent (Momentive Performance Materials (former company: GE TOSHIBA Silicone), TSL8350, γ-glycidoxypropyltrimethoxysilane), carbodiimide group 31.2 parts by mass of a compound ("Carbodiide (registered trademark) SV-02" by Nisshinbo Corporation, polycarbodiimide, Mw: 2,700, 40 mass% of solid content), and 72.8 mass parts of ion-exchange water are added, and it stirred for 10 minutes, An emulsion (emulsion) of the olefin-acid copolymer and the carboxylic acid polymer was prepared (about 20 mass% of solid content concentration and measured according to JIS K6833).

Experimental Example 1-1 to 1-10

<Preparation of Surface Treatment Composition>

In the emulsion, a colloidal silica (A) having a surface area average particle diameter of 4 to 6 nm (notarized value) (manufactured by Nissan Chemical Co., Ltd., Snowtex® XS (solid content concentration of 20%)) and a surface area average particle diameter of 10 to 20 nm Colloidal silica (B) of (notarized value) (Snowtex (registered trademark) 40 (solid content concentration 40%) by Nissan Chemical Co., Ltd.) was added sequentially, and after mixing them well, glycidoxy group containing silane coupler A ring agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403 (solid content concentration: 100%)) was added, followed by sodium metavanadate (manufactured by Shinko Chemical Co., Ltd., sodium metavanadate (solid content concentration: about 66%)) as metavanadate. An acrylic modified epoxy resin (made by Arakawa Chemical Co., Ltd., Modepix® 302 (solid content concentration 33.5%)) was further added to this mixture, and the surface treatment composition was produced.

In addition, the mixing amount (or mixing ratio) of each component in preparation of the said surface treatment composition is as follows.

Mass ratio of colloidal silica (A) and (B): 50:50

Mass ratio of the inorganic component and the resin component (mixing amount of the total solid in the emulsion with an acrylic modified epoxy resin, hereinafter the same): 30:70 to 95: 5

Mixed amount of acrylic modified epoxy resin: 5 mass parts (5 mass% in resin component) with respect to 95 mass parts of total solids in the said emulsion.

Mixed amount of glycidoxy group-containing silane coupling agent: 10 parts by mass based on 100 parts by mass in total of the inorganic component and the resin component

Mixed amount of metavanadate: 1 part by mass based on 100 parts by mass in total of the inorganic component and the resin component

<Production of resin coating metal plate>

As the metal plate, the surface treatment composition is applied to the surface of the steel sheet using an alkali degreased hot dip galvanized steel sheet GI material (Zn deposition amount 45 g / m ² ) or an alloyed hot dip galvanized steel sheet GA material (Zn deposition amount 45 g / m ² ). It coated with the coating (bar No. 3 or 4), and it heat-dried for about 12 second at plate temperature 90 degreeC, and produced the resin coating metal plate whose resin film adhesion amount is 0.5 g / m <^2> . Table 1 shows the evaluation results of the obtained resin-coated metal sheet.

(Experimental Example 1-11)

<Preparation of Surface Treatment Composition>

Lithium silicate with a SiO ₂ / Li ₂ O molar ratio of 4.5 ("Lithium silicate 45" manufactured by Nissan Chemical Co., Ltd.) and colloidal silica having a surface area average particle diameter (notarized value) of 4 to 6 nm (manufactured by Nissan Chemical Co., Ltd., Snowtex (registered trademark) ) XS) was mixed in a mass ratio of 90:10 to prepare an inorganic component.

After adding the inorganic component obtained to the said emulsion and mixing both well, a glycidoxy group containing silane coupling agent (made by Shin-Etsu Chemical Co., Ltd., KBM403, (gamma)-glycidoxy propyl triethoxysilane), and then metabanad Sodium acid (made by Shinko Chemical Co., Ltd., sodium metavanade) was added. An oxazoline group-containing copolymer (manufactured by Nippon Shokubai Co., Epocross (registered trademark) K-2030E, solid content: 40% by mass) was further added to this mixture to prepare a surface treatment composition.

In addition, the mixing amount (or mixing ratio) of each component in preparation of the said surface treatment composition is as follows.

Mixing ratio of the inorganic component and the mixture of the total solids and the oxazoline group-containing copolymer in the emulsion: 70:30

Mixed amount of oxazoline group containing copolymer: 5 mass parts with respect to 95 mass parts of total solids in the said emulsion

Mixed amount of glycidyl group containing silane coupling agent: 15 mass parts with respect to a total of 100 mass parts of an inorganic component, the mixture of the total solid in an said emulsion, and an oxazoline group containing copolymer.

Mixing amount of sodium metavanadate: 5 parts by mass based on 100 parts by mass in total of the inorganic component and the mixture of the total solid in the emulsion and an oxazoline group-containing copolymer.

<Production of resin coating metal plate>

A resin-coated metal sheet was produced in the same manner as Experimental Example 1-1 except that the surface treatment composition prepared in Experimental Example 1-11 was used. Table 1 shows the evaluation results of the obtained resin-coated metal sheet.

Experimental Example 2-1 to 2-10

<Preparation of Surface Treatment Composition>

A surface treatment composition was prepared in the same manner as in Experimental Example 1-3 except that the mass ratio of colloidal silica (A) and colloidal silica (B) was changed from 100: 0 to 0: 100.

<Production of resin coating metal plate>

The resin-coated metal plate was produced like Example 1 1-3 except having used the surface treatment composition prepared in Experimental example 2-1-2-10. Table 2 shows the evaluation results of the obtained resin-coated metal sheet.

Experimental Example 2-11 to 2-12

Instead of colloidal silica (B), a colloidal silica (Nesan Chemical Co., Snowtex (registered trademark) 50) having a surface area average particle diameter of 20 to 30 nm (notarized value) or a surface area average particle diameter of 40 to 50 nm (notarized value) A surface treatment composition was prepared in the same manner as Experimental Example 2-1 except that colloidal silica (20L of Snowtex (registered trademark) manufactured by Nissan Chemical Industries, Ltd.) was used.

<Production of resin coating metal plate>

A resin-coated metal sheet was produced in the same manner as in Experimental Example 2-1 except that the surface treatment composition prepared in Experimental Examples 2-11 to 2-12 was used. Table 2 shows the evaluation results of the obtained resin-coated metal sheet.

Experimental Examples 3-1 to 3-11

<Preparation of Surface Treatment Composition>

Surface treatment was carried out in the same manner as Experimental Example 1-3 except that the mixed amount of the acrylic modified epoxy resin was 0 to 20 parts by mass (0 to 20% by mass in the resin component) based on 80 to 100 parts by mass of the total solids in the emulsion. The composition was produced.

<Production of resin coating metal plate>

Resin-coated metal sheets were produced in the same manner as Experimental Examples 1-3 except that the surface treatment compositions prepared in Experimental Examples 3-1 to 3-11 were used. Table 3 shows the evaluation results of the obtained resin-coated metal sheet.

(Experimental Examples 4-1 to 4-9)

<Preparation of Surface Treatment Composition>

A surface treatment composition was produced in the same manner as Experimental Example 1-3 except that the amount of the glycidoxy group-containing silane coupling agent mixed was 0 to 20 parts by mass based on 100 parts by mass of the total of the inorganic component and the resin component.

<Production of resin coating metal plate>

Resin-coated metal sheets were produced in the same manner as in Experimental Examples 1-3 except for using the surface treatment compositions prepared in Experimental Examples 4-1 to 4-9. Table 4 shows the evaluation results of the obtained resin-coated metal sheet.

Experimental Examples 5-1 to 5-10

<Preparation of Surface Treatment Composition>

A surface treatment composition was prepared in the same manner as in Experimental Example 1-3 except that the mixed amount of metavanadate was 0 to 5 parts by mass based on 100 parts by mass of the total of the inorganic component and the resin component.

<Production of resin coating metal plate>

The resin-coated metal sheet was produced like Example 1-1 except having used the surface treatment composition prepared in Experimental example 5-1-5-10. Table 5 shows the evaluation results of the obtained resin-coated metal sheet.

Experimental Examples 6-1 to 6-8

<Production of resin coating metal plate>

A resin-coated metal sheet was produced in the same manner as Experimental Example 1-3 except that the resin coating amount was adjusted to 0.1 to 1.5 g / m ² . Table 6 shows the evaluation results of the obtained resin-coated metal sheet.

The present invention can provide a resin-coated metal sheet that satisfies not only the corrosion resistance but also the roll moldability required by the GI material and the coating film adhesion after the post-coating required by the GA material.

Claims (6)

As a resin coating metal plate provided with the resin film obtained from a surface treatment composition, the said surface treatment composition is
60 to 80 parts by mass of an inorganic component composed of a plurality of colloidal silicas having different surface area average particle diameters,
While containing 20 to 40 parts by mass of a resin component composed of an olefin-α, β-unsaturated carboxylic acid copolymer, an α, β-unsaturated carboxylic acid polymer and an acrylic modified epoxy resin,
5 to 15 parts by mass of glycidoxy group-containing silane coupling agent and 0.5 to 3 parts by mass of metavanadate, based on 100 parts by mass of the inorganic component and the resin component in total,
The resin coating metal plate in which the said resin component contains 2-15 mass% of said acrylic modified epoxy resins. The method of claim 1,
The inorganic component comprises a colloidal silica (A) having a surface area average particle diameter of 4 to 6 nm and a colloidal silica (B) having a surface area average particle diameter of 10 to 20 nm, wherein a mixing ratio of (A) and (B) is 70: The resin coating metal plate which is 30-40: 60 (mass ratio). delete 3. The method according to claim 1 or 2,
The resin coating metal plate whose surface tension of the said surface treatment composition is 50 dyn / cm or less. 3. The method according to claim 1 or 2,
The resin coating metal plate whose adhesion amount of the said resin film is 0.2-1 g / m <^2> in dry mass. 3. The method according to claim 1 or 2,
A resin coated metal sheet, wherein the metal sheet provided with the resin film is a hot dip galvanized steel sheet or an alloyed hot dip galvanized steel sheet.