JP6946377B2 - Resin coated metal plate - Google Patents

Description

The present invention relates to a resin-coated metal plate on which a resin film is laminated and has excellent slidability. Further, when a coated plate in which paint is applied to a resin-coated metal plate (hereinafter, simply referred to as a coated plate) is used, it is excellent in salt water resistance and adhesion between the coating film and the resin film (hereinafter referred to as coating film adhesion). Regarding a resin-coated metal plate to be a painted plate.

Examples of the hot-dip galvanized metal plate used for building materials include a hot-dip galvanized metal plate (GI) in which a metal plate is plated with pure zinc and an alloyed hot-dip galvanized metal plate (GA) obtained by alloying the metal plate. Then, as a method of applying the paint to these metal plates, after the metal plate is bent or rolled into a desired shape, the metal plate surface is dipped or sprayed by means such as spray paint or powder. After applying a paint, electrodeposition paint, etc., a method of drying at room temperature or baking, that is, a so-called post-coating method is used.

Further, conventionally, the surface of GI, GA or the like has been subjected to chromate treatment. By doing so, it is possible to improve the adhesion of the coating film and the corrosion resistance of the coated plate. However, in recent years, due to heightened environmental awareness, a treatment method without chromate treatment (non-chromate treatment) has been studied, and a resin-coated metal plate in which a chromate-free resin film is formed on a hot-dip galvanized metal plate. Therefore, resin-coated metal plates having excellent corrosion resistance, coating adhesion, processability, and the like have been developed.

For example, Patent Documents 1 and 2 disclose a non-chromium type surface-treated metal material having a film containing an organic resin, a phosphoric acid compound, fine silica and the like on the upper layer of the metal material.

The non-chromium type surface-treated metal materials of Patent Documents 1 and 2 are excellent for single-shot processing such as cylindrical deep drawing processing, draw bead processing, and Eriksen processing. However, in building material applications, a metal material is continuously passed through a plurality of sets of molding rolls arranged in a row (molding speed of about 20 to 70 m / min) to transform a flat plate into a molded product having a desired cross-sectional shape (formation). It is often rolled) and is repeatedly slid, but the non-chromium type surface-treated metal materials of Patent Documents 1 and 2 are applied to the non-chromium type surface-treated metal material when they are repeatedly slid. The paint is easily peeled off and the slidability is insufficient.

Further, the non-chromium type surface-treated metal materials of Patent Documents 1 and 2 are excellent in the coating film adhesion of the coated plate which is cured by baking the paint applied to the surface-treated metal plate. However, in the application of building materials, the coating film is often dried at room temperature after spray coating, and the coating film applied to the non-chromium type surface-treated metal material of Patent Documents 1 and 2 is dried at room temperature and cured. The coating film adhesion is insufficient.

On the other hand, Patent Documents 3 and 4 disclose a resin-coated metal plate provided with a resin film obtained from the surface treatment composition. The surface treatment compositions of Patent Documents 3 and 4 include colloidal silica, olefin-α, β-unsaturated carboxylic acid copolymer, α, β-unsaturated carboxylic acid polymer, oxazoline group-containing copolymer and the like. It has been.

However, the resin-coated metal plates of Patent Documents 3 and 4 also have excellent coating adhesion of the coated plate that has been cured by baking the paint applied to the resin-coated metal plate, but the paint applied to the resin-coated metal plate is at room temperature. The coating adhesion of the coated plate that has been dried and cured is insufficient.

Further, Patent Document 5 also discloses a resin-coated metal plate provided with a resin film obtained from the surface treatment composition. The surface treatment composition of Patent Document 5 contains colloidal silica, olefin-α, β-unsaturated carboxylic acid copolymer, α, β-unsaturated carboxylic acid polymer and the like, and the colloidal silica includes. Multiple types of colloidal silica having different surface average particle diameters are used.

In Patent Document 5, the adhesiveness of a coating film is evaluated by using a spray-type calcium leadate rust preventive paint which is often used for building materials. However, due to the growing environmental awareness in recent years, harmful substance-free paints that do not contain chromium, lead, etc. are being developed for paints applied to resin-coated metal plates. Calcium leadate can keep the coating film and metal interface weakly alkaline and suppress corrosion such as swelling of the coating film even when moisture or acidic substances permeate in the coating film, but it is a harmful substance-free paint. In this case, since a compound such as zinc or titanium is used instead of lead, corrosion such as swelling of the coating film is likely to occur. Further, the resin-coated metal plate of Patent Document 5 has a good adhesion between the harmful substance-free coating film and the resin-coated metal plate, and particularly, the adhesion between the harmful substance-free coating film and the resin-coated metal plate after immersion in boiling water. There was room for improvement.

Japanese Unexamined Patent Publication No. 2000-248384 Japanese Unexamined Patent Publication No. 2000-248369 Japanese Unexamined Patent Publication No. 2009-061608 Japanese Unexamined Patent Publication No. 2009-255549 Japanese Unexamined Patent Publication No. 2011-092837

The present invention has been made in view of the above circumstances, and an object of the present invention is a resin-coated metal plate having excellent slidability, and when a paint is post-coated on the resin-coated metal plate. (In particular, when a harmful substance-free paint is applied to a resin-coated metal plate and dried at room temperature to cure), it is an object of the present invention to provide a resin-coated metal plate that becomes a coating plate having excellent salt water resistance and coating adhesion. ..

The resin-coated metal plate of the present invention that has solved the above problems is a resin-coated metal plate in which a resin film containing colloidal silica and a resin component is laminated on at least one surface of the metal plate. The content of the colloidal silica is 30 to 80 parts by mass and the content of the colloidal silica having a particle size of less than 10 nm exceeds 15 parts by mass in a total of 100 parts by mass of the resin component. It is characterized in that the amount of sodium eluted when the coated metal plate is immersed in deionized water at 100 ° C. for 10 seconds is 4 mg / m ^{2 or less.}

The colloidal silica preferably contains ammonia-stabilized colloidal silica. Further, the colloidal silica is preferably composed of a plurality of types of colloidal silica having different average particle diameters, and the colloidal silica has an average particle diameter of 4 to 6 nm and a colloidal silica having an average particle diameter of 10 to 15 nm. It is more preferable that the mass ratio of colloidal silica having an average particle diameter of 4 to 6 nm and colloidal silica having an average particle diameter of 10 to 15 nm is 80:20 to 30:70.

The resin component preferably contains an olefin-α, β-unsaturated carboxylic acid copolymer, and more preferably contains an α, β-unsaturated carboxylic acid polymer.

The resin-coated metal plate of the present invention can be made into a resin-coated metal plate having excellent slidability by providing a resin film obtained from a predetermined surface treatment composition. In addition, when the paint is post-coated on the resin-coated metal plate (especially when the harmful substance-free paint is applied to the resin-coated metal plate and dried at room temperature to cure), the coating has excellent salt water resistance and coating adhesion. It can be a board.

The resin-coated metal plate of the present invention is obtained by laminating a resin film containing colloidal silica and a resin component on at least one surface of the metal plate. Hereinafter, the resin-coated metal plate of the present invention will be described in detail. Although the film of the present invention may contain much more colloidal silica than the resin component, the term "resin film" is also used in the present invention because it is often referred to as "resin film" in this field. Further, in the present specification, "sliding" means the slidability of the resin-coated metal plate, and "salt-resistant" means the salt-water resistance of the coated plate coated with the paint on the resin-coated metal plate. That is. Further, in the present specification, the "primary adhesion" is the adhesion (coating adhesion) between the coating film and the resin film on the coated plate in which the paint is applied to the resin-coated metal plate, and is "secondary adhesion". "Adhesion" refers to the adhesion between the coating film and the resin film (coating film adhesion) after the coated plate coated with paint is immersed in boiling water, and is referred to as "coating film adhesion". Is the adhesion of both the primary adhesion and the secondary adhesion.

<Metal plate>
The metal plate used in the present invention is not particularly limited, and is, for example, a non-plated cold-rolled metal plate, a hot-dip zinc-plated metal plate (GI), an alloyed hot-dip zinc-plated metal plate (GA), and an electrozinc-plated metal plate (EG). , Aluminum plate, titanium plate and the like. Among these, it is preferable to apply the present invention to a hot-dip galvanized metal plate (GI) or an alloyed hot-dip galvanized metal plate (GA) that has not been subjected to chromate treatment.

<Coroidal silica>
The colloidal silica contained in the film is 30 to 80 parts by mass, more preferably 40 to 75 parts by mass, and further preferably 50 to 70 parts by mass in a total of 100 parts by mass of the colloidal silica and the resin component. be. When a surface treatment composition in which colloidal silica is within the above range is used, the resin film to be formed has good film-forming properties, so that film peeling is unlikely to occur and slidability is improved. Further, the surface tension of the surface treatment composition is lowered, the surface roughness is rough, and the surface treatment composition invades the surface (recess) of GA having poor water wettability, and the resin is formed along the rough surface of GA. Since a film is formed, the adhesion of the coating film is also improved.

If the amount of the colloidal silica component exceeds 80 parts by mass, the resin component is insufficient, so that the film-forming property of the film to be formed becomes insufficient, and a normal film cannot be formed. As a result, the film becomes too hard and brittle, cracks are generated, the film is easily peeled off during roll molding, and the slidability is lowered. Further, since colloidal silica (amorphous silica particles are dispersed in water to form a colloid) has a high surface tension, the surface tension of the surface treatment composition becomes large when the amount of the component of colloidal silica exceeds 80 parts by mass. As a result, the wettability with the metal plate on which the resin film is formed is also deteriorated, and it may be difficult to uniformly form the thin film film. In particular, it becomes difficult to form a uniform and ultra-thin film on the uneven portion of the GA surface, so that the coating film adhesion is lowered.

If the amount of the colloidal silica component is less than 30 parts by mass, the hardness of the film is insufficient, the film damage due to repeated sliding becomes remarkable, and the specific gravity of the film does not increase so much, so that it is difficult to thin the resin film. Therefore, film peeling is likely to occur during roll molding. Further, since the specific gravity of the resin film does not increase, the film residue cannot be settled in the coolant liquid receiving tank, and the effect of suppressing the accumulation on the surface of the drain pad is insufficient, resulting in operability. And may worsen the product shape.

The resin film contains colloidal silica, and the content of colloidal silica having a particle size of less than 10 nm (hereinafter referred to as small particle size colloidal silica) is 15 mass by mass in a total of 100 parts by mass of the colloidal silica and the resin component. It is necessary beyond the department. When the amount of colloidal silica having a small particle size is small, voids are likely to be formed between the colloidal silicas, and even when the amount of sodium in the film is controlled by water permeation, the salt water resistance of the coating film dried at room temperature And the secondary adhesion may deteriorate. The details of the amount of sodium in the film will be described later, but it is preferable to use ammonia-stabilized colloidal silica in order to control the amount of sodium in the film.

Further, it is preferable to use a plurality of types of colloidal silica having different average particle sizes. As a result, the affinity (familiarity) between the binder resin (resin component) and colloidal silica is improved, the film-forming property (bonding force between colloidal silica particles) of the formed resin film is improved, and a dense film is formed. Can be formed.

More preferably, colloidal silica having a small particle size and colloidal silica having a particle size of 10 nm or more (hereinafter referred to as colloidal silica having a large particle size) are used. At the same time as the bonding force between the colloidal silicas increases to form a dense film, the colloidal silicas with a small particle size are dispersed between the colloidal silicas with a small particle size to form a micro-concavo-convex surface structure. By receiving it, the rolling property is improved, and further, the unevenness improves the primary adhesion. Further, as described above, small particle size colloidal silica is indispensable, but on the other hand, since small particle size colloidal silica has high surface activity, if only small particle size colloidal silica is used, the surface treatment composition The liquid stability of the product deteriorates over time (thickening takes about 48 hours), and a dense film may not be formed. Therefore, the content of colloidal silica in the resin film may be increased to increase the specific gravity of the resin film. It may not be possible. However, if a small particle size colloidal silica and a large particle size colloidal silica having a small surface activity are used in combination, the content of the colloidal silica can be increased without lowering the liquid stability of the surface treatment composition.

More preferably, it is composed of colloidal silica having an average particle diameter of 4 to 6 nm (hereinafter referred to as colloidal silica (A)) and colloidal silica having an average particle diameter of 10 to 15 nm (hereinafter referred to as colloidal silica (B)). Most preferably, it is composed of colloidal silica (A) and colloidal silica (B). As the large particle size colloidal silica, colloidal silica having an average particle size of more than 15 nm may be contained, but when only a large particle size colloidal silica having an average particle size of more than 15 nm is used, small particles are used. The difference in particle size from colloidal silica in diameter becomes too large, and the film-forming property may be lowered, and the secondary adhesion and slidability may be lowered.

The mixing ratio of colloidal silica (A) and colloidal silica (B) is preferably 80:20 to 30:70, more preferably 75:25 to 40:60, and even more preferably 65:35 to 45:55 in terms of mass ratio. .. If the mass ratio of colloidal silica (A) is larger than the above ratio, the affinity with the resin component is deteriorated, the liquid stability of the surface treatment composition is deteriorated, and a uniform and dense film may not be formed. .. Along with this, the coating film adhesion of the post-coated coated plate deteriorates. When the mass ratio of colloidal silica (A) is smaller than the above ratio, the film-forming property is lowered, so that the film density is lowered, and the secondary adhesion and salt water resistance may be deteriorated.

When the surface treatment composition used for forming the resin film is water-based, it is preferable to select the type of colloidal silica according to the pH of the surface treatment composition in order to disperse the colloidal silica well.

Colloidal silica is commercially available. For example, "Snowtex (registered trademark)" manufactured by Nissan Chemical Industries, Ltd. has an average particle size of 4 to 6 nm, which corresponds to colloidal silica (A) having a small particle size. Examples thereof include "XS", "Snowtex (registered trademark) NXS", and "Snowtex (registered trademark) OXS". In particular, ammonia-stabilized "Snowtex® NXS" is preferably used to control the amount of sodium in the coating.
Further, as those having an average particle diameter of 10 to 15 nm corresponding to colloidal silica (B) having a large particle size, "Snowtex (registered trademark) 30" and "Snowtex (registered trademark) 30" also manufactured by Nissan Chemical Industries, Ltd. Examples thereof include "Snowtex (registered trademark) N30G", "Snowtex (registered trademark) N", and "Snowtex (registered trademark) O". In order to control the amount of sodium in the film, "Snowtex (registered trademark) N30G" and "Snowtex (registered trademark) N" stabilized with ammonia are particularly preferably used.

Furthermore, for those with an average particle size of 20 to 25 nm, "Snowtex (registered trademark) 50", "Snowtex (registered trademark) N-40", and "Snowtex (registered trademark)" also manufactured by Nissan Chemical Industries, Ltd. "O-40" has an average particle size of 8 to 11 nm, and is also manufactured by Nissan Chemical Industries, Ltd. "Snowtex (registered trademark) S", "Snowtex (registered trademark) NS", and "Snowtex (registered trademark)". ) OS ”and the like. In order to control the amount of sodium in the film, "Snowtex (registered trademark) N-40" and "Snowtex (registered trademark) NS" stabilized with ammonia are particularly preferably used.

In addition, "Adelite (registered trademark) AT-20", "Adelite (registered trademark) AT-30", and "Adelite (registered trademark) AT-40" manufactured by ADEKA Corporation have an average particle size of 10 to 20 nm. , "Adelite (registered trademark) AT-20N" and the like. In particular, ammonia-stabilized "Adelite® AT-20N" is preferably used to control the amount of sodium in the coating.
The average particle size of colloidal silica in the present specification is a value measured by the Sears method when the average particle size is about 1 to 10 nm and by the BET method when the average particle size is about 10 to 100 nm. If the notarized value is stated in the manufacturer's pamphlet, the notarized value shall be the average particle size.

When the pH of the surface treatment composition is alkaline, it can be suitably used by adding ammonia or amine to acidic type colloidal silica. Examples of amines to be added are tertiary amines such as triethylamine, N, N-dimethylbutylamine, N, N-dimethylallylamine, N-methylpyrrolidin, tetramethyldiaminomethane, trimethylamine; N-methylethylamine, diisopropylamine, diethylamine. Secondary amines such as propylamine, t-butylamine, sec-butylamine, isobutylamine, 1,2-dibutylpropylamine, 3-pentylamine and the like, and one or more are mixed. Can be used. Of these, tertiary amines are preferred, with triethylamine being the most preferred.

Commercially available acidic type colloidal silicas include "Snowtex (registered trademark) OXS", "Snowtex (registered trademark) O", "Snowtex (registered trademark) O-40", and "Snowtex (registered trademark)". OS ”and the like.

Further, a commercially available product of amine-stabilized colloidal silica can also be preferably used. For example, "Snowtex (registered trademark) QAS-25" and "Snowtex (registered trademark) QAS-40" manufactured by Nissan Chemical Industries, Ltd. having an average particle size of 10 to 15 nm can be mentioned.

(Amount of sodium eluted from the resin film)
Colloidal silica is generally produced by removing sodium from water glass (Na ₂ SiO ₃ ) by ion exchange, and a small amount of sodium remains in order to stabilize colloidal silica. When the resin component is an aqueous emulsion (aqueous dispersion), sodium may be added to stabilize the emulsion.

When a salt water resistance test or a secondary adhesion test is performed on a post-coated coated plate, the water that has permeated the coating film redissolves the sodium content in the coating film, and an alkaline component is generated at the coating film or resin film interface. .. The alkaline component acts on the ester bond of the coating film and cuts it, causing poor adhesion of the coating film.

The amount of sodium in the film is very small (at most, about 1% of the film mass), and in baking type paints, the degree of polymerization of the coating film is high, so a small amount of alkaline components are generated at the interface between the coating film and the resin film. However, the problem did not become apparent. Further, even in the case of the room temperature drying type paint having a lower degree of polymerization polymerization than the baking type paint, no actual damage was observed in the case of the calcium leadate paint because calcium leadate exhibits a pH buffering action. However, when a lead-free paint of a room temperature drying type is used, salt water resistance and secondary adhesion may be insufficient, and it is necessary to control a trace amount of sodium in the film.

The amount of sodium eluted from the resin film when the resin-coated metal plate is immersed in deionized water at 100 ° C. for 10 seconds is 4 mg / m ² or less, preferably 3 mg / m 2 or less, more ^{preferably 3 mg / m 2.} It is 2.5 mg / m ² or less. The method for quantifying sodium eluted from the resin film will be described in detail in Examples.

<Resin component>
The resin component contained in the film is 20 to 70 parts by mass, more preferably 25 to 60 parts by mass, and further preferably 30 to 50 parts by mass in 100 parts by mass of the total of colloidal silica and the resin component. be. In the surface treatment composition in which the resin component is within the above range, the film-forming property of the formed resin film is good, so that film peeling is unlikely to occur and the slidability is improved.

The resin component is not particularly limited, and a polyurethane resin, a polyolefin resin, a polyester resin, a polyacrylic resin, a fluorine resin, a silicone resin, a mixed or modified resin thereof, or the like is appropriately used. can do. Among them, polyolefin-based resins (more preferably polyethylene-based resins) and polyurethane-based resins are preferable in that excellent liquid stability can be obtained. The resin may be used alone or in combination of two or more.

(Polyolefin resin)
The polyolefin-based resin used in the present invention is not particularly limited, but the polyolefin-based resin is an olefin-α, β-unsaturated carboxylic acid copolymer (hereinafter, may be referred to as “olefin-acid copolymer”). It is preferably contained, and more preferably composed of an olefin-acid copolymer. When the resin component contains an olefin-acid copolymer, salt water resistance and slidability are improved.

The "olefin-acid copolymer" in the present invention is a copolymer of an olefin and an α, β-unsaturated carboxylic acid, and the constituent unit derived from the olefin is 50% by mass in the copolymer. It means the above (that is, the constituent unit derived from α, β-unsaturated carboxylic acid is 50% by mass or less).

(Olefin-acid copolymer)
The olefin-acid copolymer can be produced by copolymerizing an olefin with an α, β-unsaturated carboxylic acid by a known method, and is commercially available. As the olefin-acid copolymer, one kind or two or more kinds can be used.

The olefin that can be used for producing the olefin-acid copolymer is not particularly limited, but ethylene, propylene and the like are preferable, and ethylene is more preferable. The olefin-acid copolymer may be derived from only one type of olefin or two or more types of olefins.

The α, β-unsaturated carboxylic acids that can be used in the production of olefin-acid copolymers are also not particularly limited, and are monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid and isocrotonic acid; maleic acid, fumaric acid, etc. Examples thereof include dicarboxylic acids such as itaconic acid. Of these, acrylic acid is preferable. In the olefin-acid copolymer, the constituent unit of the α, β-unsaturated carboxylic acid may be derived from only one kind of α, β-unsaturated carboxylic acid, or two or more kinds of α, It may be derived from β-unsaturated carboxylic acid.

The α, β-unsaturated carboxylic acid in the olefin-acid copolymer has an action of improving the adhesion between the resin film and the metal plate, and in order to effectively exert such an action, the co-weight is used. The α, β-unsaturated carboxylic acid in the coalescence is preferably 5% by mass or more, more preferably 10% by mass or more. On the other hand, the upper limit of α, β-unsaturated carboxylic acid in the copolymer is preferably 30% by mass or less, more preferably 25% by mass or less, from the viewpoint of corrosion resistance.

The olefin-acid copolymer may have a structural unit derived from other monomers as long as it does not adversely affect the slidability, coating film adhesion, etc., which are the effects of the present invention. In the olefin-acid copolymer, the amount of structural units derived from other monomers is preferably 10% by mass or less, more preferably 5% by mass or less, and the most preferable olefin-acid copolymer is an olefin. It is composed only of − and α, β-unsaturated carboxylic acids. Preferred olefin-acid copolymers include ethylene-acrylic acid copolymers.

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

(Α, β-unsaturated carboxylic acid polymer)
The polyolefin-based resin preferably contains an olefin-acid copolymer and an α, β-unsaturated carboxylic acid polymer (hereinafter sometimes referred to as “carboxylic acid polymer”), and preferably contains an olefin-acid copolymer and a carboxylic acid. It is more preferably composed of an acid polymer. When the resin component further contains a carboxylic acid polymer, salt water resistance and slidability are further improved. The exact mechanism is unknown, but it is presumed that this is because the binding force between these polymers and colloidal silica is increased, a dense resin film is formed, and water permeation is effectively suppressed. Will be done.

The "carboxylic acid polymer" in the present invention is a polymer (including a copolymer) obtained by polymerizing using α, β-unsaturated carboxylic acid as a monomer, and is α, β-. It means that the constituent unit derived from unsaturated carboxylic acid is 90% by mass or more in the polymer. The "α, β-unsaturated carboxylic acid" also includes "α, β-unsaturated carboxylic acid salt" in which a part of the carboxyl group is neutralized with a neutralizing agent described later.

The carboxylic acid polymer is a copolymer or copolymer of one or more α, β-unsaturated carboxylic acids, or a copolymer obtained by copolymerizing another monomer (excluding olefins). Polymers can be mentioned. Such carboxylic acid polymers can be produced by known methods and are commercially available. As the carboxylic acid polymer, one kind or two or more kinds can be used.

As the α, β-unsaturated carboxylic acid that can be used in the production of the carboxylic acid polymer, any 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. be. Among these, acrylic acid or maleic acid is preferable, and maleic acid is more preferable.

The carboxylic acid polymer may contain a structural unit derived from a monomer other than α, β-unsaturated carboxylic acid, but the amount of the structural unit derived from the other monomer is contained in the polymer. It is 10% by mass or less, preferably 5% by mass or less, and a carboxylic acid polymer composed only of α, β-unsaturated carboxylic acid is more preferable.

Preferred carboxylic acid polymers include, for example, polyacrylic acid, polymethacrylic acid, acrylic acid-maleic acid copolymer, polymaleic acid, etc. Among these, coating adhesion and adhesion between the resin film and the metal plate can be mentioned. Polymaleic acid is more preferable from the viewpoint of properties and the like. By using polymaleic acid, the particle size of the produced resin emulsion becomes small (20 to 60 nm), and the film obtained by forming the film becomes dense, so that the slidability and the like are improved. Further, since polymaleic acid has a large amount of carboxyl groups, the adhesion between the resin film and the metal plate is improved.

The weight average molecular weight (Mw) of the carboxylic acid polymer 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 in terms of polystyrene. It is 000. This Mw can be measured by GPC using polystyrene as a standard.

The content ratio (mass ratio) of the olefin-acid copolymer and the carboxylic acid polymer in the polyolefin resin is preferably 1,000: 1 to 10: 1, more preferably 200: 1 to 20: 1, and further. It is preferably 100: 1 to 100: 3. If the content ratio of the carboxylic acid polymer is too low, the effect of combining the olefin-acid copolymer and the carboxylic acid polymer may not be sufficiently exhibited, and conversely, the content ratio of the carboxylic acid polymer is excessive. In the composition, the olefin-acid copolymer and the carboxylic acid polymer may be phase-separated, and the resin film may not be uniformly formed.

(Polyurethane resin)
The polyurethane-based resin used in the present invention is not particularly limited, but is more preferably a carboxyl group-containing polyurethane resin. The carboxyl group-containing polyurethane resin is obtained by chain-extending a urethane prepolymer with a chain extender, and the urethane prepolymer is obtained by reacting a polyisocyanate component described later with a polyol component. As the polyisocyanate component constituting the urethane prepolymer, at least one polyisocyanate selected from the group consisting of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI) and dicyclohexylmethane diisocyanate (hydrogenated MDI) is used. Is preferable. This is because by using such a polyisocyanate, a resin film having excellent corrosion resistance and stability of reaction control can be obtained. In addition to the above-mentioned suitable polyisocyanate, other polyisocyanate can be used as long as the corrosion resistance and the stability of reaction control are not deteriorated, but the content of the suitable polyisocyanate component is 70% by mass of the total polyisocyanate component. It is desirable to do the above. This is because if the content of the suitable polyisocyanate component is less than 70% by mass, the corrosion resistance and the stability of reaction control tend to decrease. Examples of polyisocyanates other than the above-mentioned suitable polyisocyanate components include tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, and phenylene diisocyanate. The polyisocyanate may be used alone or in combination of at least two or more.

As the polyol component constituting the urethane prepolymer, it is preferable to preferably use all three types of polyols: 1,4-cyclohexanedimethanol, polyether polyol, and polyol having a carboxyl group. All may be diols. This is because a resin film having excellent corrosion resistance and slidability can be obtained by using such a polyol component. Further, by using 1,4-cyclohexanedimethanol as the polyol component, the rust preventive effect of the obtained polyurethane resin can be enhanced.

The above-mentioned polyether polyol is not particularly limited as long as it has at least two hydroxyl groups in the molecular chain and the main skeleton is composed of alkylene oxide units. For example, polyoxyethylene glycol (simply, "Polyethylene glycol"), polyoxypropylene glycol (sometimes referred to simply as "polypropylene glycol"), polyoxytetramethylene glycol (simply "polytetramethylene glycol" or "polytetramethylene") It may be referred to as "ether glycol"), and commercially available products can be used. Among the above-mentioned polyether polyols, it is preferable to use polyoxypropylene glycol or polytetramethylene ether glycol. The number of functional groups of the polyether polyol is not particularly limited as long as it is at least 2 or more, and may be, for example, trifunctional or tetrafunctional or higher.

The above-mentioned polyether polyol can be obtained, for example, by adding an alkylene oxide such as ethylene oxide or propylene oxide using a compound having active hydrogen as an initiator. Examples of the compound having active hydrogen include diols such as propylene glycol and ethylene glycol, triols such as glycerin, trimethylolpropane, hexanetriol and triethanolamine, tetraols such as diglycerin and pentaerythritol, and sorbitol. Examples thereof include sucrose and phosphoric acid. At this time, if a diol is used as the initiator to be used, a bifunctional polyether polyol can be obtained, and if triol is used, a trifunctional polyether polyol can be obtained.

Further, polyoxytetramethylene glycol can be obtained by, for example, ring-opening polymerization of tetrahydrofuran.

As the polyether polyol, for example, it is preferable to use a commercially available product having an average molecular weight of about 400 to 4000. This is because if the average molecular weight is less than about 400, the resin film becomes hard, and if it exceeds 4000, the resin film becomes too soft. The average molecular weight is obtained from the OH value (hydroxyl value) of the polyol.

In the present invention, it is also a preferable embodiment that the mass ratio of the 1,4-cyclohexanedimethanol to the polyether polyol is 1,4-cyclohexanedimethanol: polyether polyol = 1: 1 to 1:19. This is because the rust preventive effect of the obtained polyurethane resin can be further enhanced by using 1,4-cyclohexanedimethanol having a rust preventive effect in a certain ratio.

The polyol having a carboxyl group used in the present invention is not particularly limited as long as it has at least one or more carboxyl groups and at least two or more hydroxyl groups, and is, for example, dimethylolpropionic acid, dimethylolbutanoic acid, and dihydroxy. Propionic acid, dihydroxysuccinic acid and the like can be mentioned.

In addition to the above-mentioned suitable polyol component, other polyols can be used as long as the corrosion resistance is not deteriorated, but the content of the suitable polyol component is preferably 70% by mass or more of the total polyol component. This is because if the content of the suitable polyol component is less than 70% by mass, the corrosion resistance tends to decrease. The polyol other than the above-mentioned suitable polyol component is not particularly limited as long as it has a plurality of hydroxyl groups, and examples thereof include a low molecular weight polyol and a high molecular weight polyol. The low molecular weight polyol is a polyol having a molecular weight of about 500 or less, and is, for example, ethylene glycol, diethylene glycol, triolethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexane. Diols such as diols; triols such as glycerin, trimethylolpropane, hexanetriol and the like can be mentioned.

The high molecular weight polyol is a polyol having a molecular weight of more than about 500, and is, for example, a condensed polyester polyol such as polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexamethylene adipate (PHMA); poly-ε. -Lactone-based polyester polyols such as caprolactone (PCL); polycarbonate polyols such as polyhexamethylene carbonate; and acrylic polyols.

The chain extender that reacts with the urethane prepolymer described above is not particularly limited, and examples thereof include polyamines, low molecular weight polyols, and alkanolamines. The same low molecular weight polyols as described above can be used, and the polyamines are aliphatic polyamines such as ethylenediamine, propylenediamine and hexamethylenediamine; tolylenediamine, xylylenediamine and diaminodiphenylmethane. Aromatic polyamines such as; alicyclic polyamines such as diaminocyclohexylmethane, piperazine and isophoronediamine; hydrazines such as hydrazine, dihydrazide succinate, dihydrazide adipate, dihydrazide phthalate and the like. Among these, it is preferable to use ethylenediamine and / or hydrazine as a chain extender component. Examples of the alkanolamine include diethanolamine and monoethanolamine.

In the present invention, it is a preferred embodiment to use the aqueous dispersion of the above-mentioned carboxyl group-containing polyurethane resin. The aqueous dispersion of the above-mentioned carboxyl group-containing polyurethane resin can be prepared by a known method. For example, the carboxyl group of the carboxyl group-containing urethane prepolymer is neutralized with a base and emulsified and dispersed in water for a chain extension reaction. It can be prepared by a method of subjecting a carboxyl group to a polyurethane resin, emulsifying and dispersing it with a high shearing force in the presence of an emulsifier, and causing a chain extension reaction. You can also do it.

<Silane coupling agent containing glycidoxy group>
The surface treatment composition of the present invention preferably contains a glycidoxy group-containing silane coupling agent (more specifically, a silane coupling agent having a glycidoxy group at the terminal). When a glycidoxy group-containing silane coupling agent is used, the adhesion between the resin film and the metal plate is improved. Further, it is considered that the colloidal silica in the resin film also has an effect of improving the binding force between the resin component, and the effect of improving the slidability and the adhesion of the coating film is large. Further, when a 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, the coatability of the surface treatment composition is improved, and the surface treatment composition is uniform. A resin film can be formed. Further, when the surface treatment composition is circulated and used by a spray ringer method (a coating method in which the surface treatment composition is sprayed on the surface of a metal plate and then squeezed with a ringer roll), foaming due to a surfactant in the composition is used. It also has the effect of suppressing.

Examples of the glycidoxy group-containing silane coupling agent include γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyldimethoxysilane.

The amount of the glycidoxy group-containing silane coupling agent in the surface treatment composition is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and preferably 7 parts by mass or more, based on 100 parts by mass of the total of colloidal silica and the resin component. It is 15 parts by mass or less, more preferably 13 parts by mass or less. If the amount of the silane coupling agent is less than 5 parts by mass, the effect of improving the adhesion between the resin film and the metal plate may not be recognized. Further, the bonding force between the colloidal silica in the resin film component and the resin component is lowered, the film hardness and the film density are lowered, and the slidability and the coating film adhesion may be insufficient. 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 resin film and the metal plate and the effect of improving the bonding force between the colloidal silica and the resin component in the resin film component reach a plateau. Therefore, it becomes a factor of cost increase. On the contrary, the slidability and the adhesion to the coating film may be lowered, or the liquid stability of the surface treatment composition may be lowered to cause gelation or precipitation of colloidal silica.

<Metavanadate>
The surface treatment composition of the present invention preferably further contains metavanadate. Metavana dinate has the effect of suppressing dissolution and elution of the metal plate by elution and improving salt water resistance and the like. In order to effectively exert this effect, it is preferable to use 0.5 to 3 parts by mass of metavanadate with respect to 100 parts by mass of the total of colloidal silica and the resin component. If it is less than 0.5 parts by mass, the above effect becomes insufficient. Further, when it is added in an amount of more than 3 parts by mass, the adhesion of the coating film tends to be remarkably lowered. It is presumed that this is because the excess metavanadate suppressed the hydrolysis reaction of the glycidoxy group-containing silane coupling agent and slightly affected the binding force between the colloidal silica and the resin component. Further, the liquid stability of the surface treatment composition tends to be deteriorated. The amount of metavanadate is more preferably 0.7 to 2.0 parts by mass. Incidentally, the preferred amount of the metavanadate salt is V ₂ O ₅ compound equivalent amount.

Examples of the metavanadate include sodium metavanadate (NaVO ₃ ), ammonium metavanadate (NH ₄ VO ₃ ), potassium metavanadate (KVO ₃ ), and the like, among which ammonium metavanadate (ammonium metavanadate) containing no monovalent metal (KVO 3) and the like. NH ₄ VO ₃ ) is preferable. These may be used alone or in combination of two or more. These metavanadates are commercially available and readily available.

<Acrylic modified epoxy resin>
The resin component preferably further contains an acrylic-modified epoxy resin as an additive. When the coating film is dried at room temperature, the adhesion of the coating film can be improved by using an acrylic-modified epoxy resin capable of forming a film at a low temperature in combination as a resin component.

Conventionally, as a method of improving the coating adhesion of a post-coated coated plate, blocked isocyanate (heat-sensitive cross-linking agent) is present in the film as a resin component, and the heat (baking temperature) at the time of baking at the time of post-coating is applied. A technique is known in which a blocking agent for blocked isocyanate is dissociated and active isocyanate groups are regenerated to cure and crosslink the coating film and the coating film. However, the calcium leadate rust preventive paint used as a postcoat paint in the field of building materials is mainly a room temperature drying type that does not require baking (drying) by heat, and the above technique cannot be used.

The exact mechanism by which the coating film adhesion is improved by using the acrylic-modified epoxy resin together is unknown, but the acrylic-modified epoxy resin does not function as a binder for colloidal silica, but forms a film on the outermost surface of the resin film ( It is presumed that the fact that they are scattered in a striped pattern contributes to the improvement of the adhesion of the coating film after post-coating. The acrylic-modified epoxy resin forms a film on the outermost surface of the resin film because the emulsion particle size of the olefin-acid copolymer or carboxylic acid polymer is 20 to 60 nm, whereas the emulsion particle size of the acrylic-modified epoxy resin is 20 to 60 nm. Is considered to be because it is as large as about 100 nm or more.

The acrylic-modified epoxy resin used in the present invention may be, for example, a copolymerization of a polymerizable unsaturated group-containing epoxy resin obtained by reacting an epoxy resin with an unsaturated fatty acid and (meth) acrylic acid, or an epoxy resin and glycidyl. It can be produced by copolymerizing a polymerizable unsaturated group-containing epoxy resin obtained by reacting a group-containing vinyl monomer with amines and (meth) acrylic acid.

In particular, water-based acrylic modified epoxy resins are commercially available, for example, "Modepix (registered trademark) 301", "Modepix (registered trademark) 302", "Modepix (registered trademark) 303", manufactured by Arakawa Chemical Industries, Ltd. Examples thereof include "Modepix (registered trademark) 304". The acrylic-modified epoxy resin may be used alone or in combination of two or more.

The acrylic-modified epoxy resin is preferably contained in an amount of 1% by mass or more (more preferably 3% by mass or more), and more preferably 15% by mass or less (more preferably 7% by mass or less) in 100% by mass of the resin component. It is preferable to have. Within the above range, the coating film adhesion of the post-coated coated plate can be improved.

When the content of the acrylic-modified epoxy resin is less than 1% by mass, the effect of improving the coating film adhesion of the post-coated coated plate is not recognized. Further, when the content of the acrylic-modified epoxy resin exceeds 15% by mass, the coating film adhesion tends to decrease. In particular, in GA, the adhesion of the coating film is significantly deteriorated, and blister may be generated. The exact mechanism by which the coating adhesion of the post-coated coated plate decreases when the content of the acrylic-modified epoxy resin exceeds 15% by mass is unknown, but due to the excessive presence of the acrylic-modified epoxy resin, It is presumed that this was because the film formation of the olefin-acid copolymer and the carboxylic acid polymer emulsion was inhibited.

<Other ingredients>
The surface treatment composition of the present invention may further contain a carbodiimide group-containing compound. The carbodiimide group can react with the carboxyl group in the olefin-acid copolymer and the carboxylic acid polymer to reduce the amount of the carboxyl group in the resin film and improve the alkali resistance. In the present invention, one or more carbodiimide group-containing compounds can be used.

Carbodiimide group-containing compounds include isocyanates such as hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (HXDI), 4,4-diphenylmethane diisocyanate (MDI) or tolylene diisocyanate (TDI). Can be produced by heating in the presence of a carbodiimidization catalyst and can be modified to be aqueous (water-soluble, hydroemulsable or water-dispersible). When the surface treatment composition is aqueous, an aqueous carbodiimide group-containing compound is preferable. Further, a compound containing a plurality of carbodiimide groups in one molecule is preferable. When a plurality of carbodiimide groups are contained in one molecule, the denseness of the film can be further improved by the cross-linking reaction with the carboxyl group in the resin component.

Commercially available carbodiimide group-containing compounds include, for example, N, N-dicyclohexylcarbodiimide, N, N-diisopropylcarbodiimide, and polycarbodiimide manufactured by Nisshinbo Co., Ltd. (a polymer having a plurality of carbodiimide groups in one molecule). One "carbodilite®" series can be mentioned. The grades of "Carbodilite (registered trademark)" include water-soluble "SV-02", "V-02", "V-02-L2", "V-04", and emulsion type "E-01". , "E-02" and the like.

The amount of the carbodiimide group-containing compound is set according to the amount of the olefin-acid copolymer and the carboxylic acid polymer which are the cross-linking partners. That is, it is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and further preferably 8 parts by mass or more with respect to 100 parts by mass of the total of the olefin-acid copolymer and the carboxylic acid polymer. On the other hand, if the amount of the carbodiimide group-containing compound becomes excessive, the effect of the combination of the olefin-acid copolymer and the carboxylic acid polymer is reduced. Further, excessive use of an aqueous carbodiimide group-containing compound in an aqueous surface treatment composition may adversely affect water resistance. From such a viewpoint, the amount of the carbodiimide group-containing compound is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and further 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 cross-linking agent, a diluent, an anti-skinning agent, a surfactant, an emulsifier, a dispersant, a leveling agent, a defoaming agent, and a penetrant as long as the effects of the present invention are not impaired. , Film-forming aids, dyes, pigments, thickeners, lubricants and the like can also be contained.

The surface treatment composition used in the present invention has been described in detail above, but a method for producing the surface treatment composition will be described below.

<Manufacturing method of surface treatment composition>
The surface treatment composition of the present invention may be either a solvent-based composition or an aqueous composition that can be applied to the surface of a metal plate, but is preferably an aqueous composition from the viewpoint of environmental problems. The surface treatment composition is 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, and an acrylic-modified epoxy. It can be prepared by blending a resin, a glycidoxy group-containing silane coupling agent, a metavanazine salt, and if necessary, a carbodiimide group-containing compound or other components in a predetermined amount and stirring.

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 the emulsion of the olefin-acid copolymer and the carboxylic acid polymer. A mixture of these was prepared, to which colloidal silica (preferably added in ascending order of average particle size on the surface), the remaining glycidoxy group-containing silane coupling agent, metavanazine salt, and acrylic-modified epoxy resin. It is preferable to add in this order. If metavanazine salt is added before the glycidoxy group-containing silane coupling agent, the hydrolysis reaction of the silane coupling agent may be suppressed and the effect of the silane coupling agent may be inhibited. Further, 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 miniaturization of the emulsion particles and, as a result, the resin film becomes denser to improve the corrosion resistance, and the silane coupling agent added later contributes to the adhesion between the resin film and the metal plate. This is because it contributes to ensuring the property and improving the adhesion of the coating film. The amount of the silane coupling agent added first is 0.1 part by mass or more (more preferably 2 parts by mass or more) with respect to 100 parts by mass in total of the olefin-acid copolymer and the carboxylic acid polymer. It is preferably 10 parts by mass or less (more preferably 7 parts by mass or less). The amount of the silane coupling agent to be added later is as described above.

It may be heated when stirring the above components. In particular, when emulsifying the olefin-acid copolymer in the presence of the carboxylic acid polymer, it is preferable to heat it.

When producing an aqueous surface treatment composition, it is preferable to emulsify an olefin-acid copolymer which is a main component of a resin component. The olefin-acid copolymer can be emulsified by using an emulsifier or by neutralizing the carboxyl group in the copolymer. When an emulsifier is used, the average particle size of the aqueous emulsion of the olefin-acid copolymer can be reduced, and the film-forming property and thereby the denseness of the resin film can be improved.

However, it is preferable to neutralize and emulsify the carboxyl group in the olefin-acid copolymer. By neutralizing and emulsifying the carboxyl group, the amount of emulsifier used can be reduced, or the emulsifier can be eliminated, and the adverse effect of the emulsifier on the water resistance and corrosion resistance of the resin film can be reduced or eliminated. be. When neutralizing the carboxyl group in the olefin-acid copolymer, a base of preferably about 0.5 to 0.95 equivalent, more preferably about 0.6 to 0.8 equivalent is used with respect to the carboxyl group. Is preferable. If the degree of neutralization is too small, the emulsifying property is not improved so much, while if the degree of neutralization is too large, the viscosity of the composition containing the olefin-acid copolymer may become too high.

As a base for neutralization, for example, a strong base composed of a group consisting of hydroxides of alkali metals and alkaline earth metals (for example, NaOH, KOH, Ca (OH) ₂ , preferably NaOH), aqueous ammonia, etc. Primary, secondary and tertiary amines (preferably triethylamine) can be mentioned. When a strong base such as NaOH is used, the emulsifying property is improved, but if the amount used is too large, the salt water resistance and the secondary adhesion may be lowered. On the other hand, amines having a low boiling point (preferably amines having a boiling point of 100 ° C. or lower under atmospheric pressure; for example, triethylamine) do not significantly reduce the above-mentioned performance of the resin film. The reason for this is considered to be that the low boiling point amine volatilizes when the surface treatment composition is applied and then heat-dried to form a resin film. However, since amine has a small effect of improving emulsifying property, it is preferable to neutralize the strong base in combination with amine. The optimal combination is a combination with triethylamine. When amine and strong base such as NaOH are used in combination, about 0.01 to 0.3 equivalent of strong base is used and 0.4 to 0 of amine is used with respect to the amount of carboxyl group of the olefin-acid copolymer. It is preferable to use about 8.8 equivalents.

When an aqueous surface treatment composition is used, a small amount of organic solvent may be blended in order to reduce the interfacial tension and improve the wettability to the 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>
The solid content of the surface treatment composition used in the present invention is not particularly limited and may be adjusted according to the method of applying the surface treatment composition to the metal plate. The solid content of the surface treatment composition is generally about 5 to 30% by mass. For example, when the surface treatment composition is sprayed on the surface of a metal plate and then squeezed with a ringer roll, the surface treatment composition is applied by a spray ringer method. About 10 to 25% by mass is preferable.

<Method of forming 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 surface treatment composition is applied to one or both sides of the surface of the metal plate by a known coating method and dried by heating. A resin-coated metal plate can be manufactured. Examples of the method for applying the surface treatment composition include a bar coater method, a curtain flow coater method, a roll coater method, a spray method, a spray ringer method, and the like. Among these, the bar coater method and the spray method are used from the viewpoint of cost and the like. The Ringer method is preferred. Further, the heating and drying conditions are not particularly limited, and the heating and drying temperature can be exemplified by about 50 to 120 ° C., preferably about 70 to 100 ° C. An excessively high heating and drying temperature is not preferable because the resin film deteriorates.

<Amount of resin film adhered>
The amount of the resin film adhered to the resin-coated metal plate is preferably 0.2 to 1.5 g / m ² and more preferably 0.3 to 1.0 g / m ² in terms of dry mass. If the amount of adhesion is ^{less than 0.2 g / m 2} , it becomes difficult to cover the surface of the metal plate, and the slidability and the adhesion of the coating film are greatly impaired. On the other hand, if the adhesion amount ^{exceeds 1.5 g / m 2} , the amount of film peeled off during roll molding increases, so the amount of film residue accumulated on the drainer pad increases, which may cause trouble. Not preferable. In addition, the adhesion of the coating film may be significantly impaired. The resin film of the present invention may contain a large amount of colloidal silica, and in that case, the specific gravity becomes large. There is. This also contributes to the reduction of film residue.

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 and implementations within the scope of the above and the following are included in the technical scope of the present invention.
In the following, "%" means "mass%" and "parts" means "parts by mass".

First, the measurement / evaluation method used in the examples will be described below.

<Amount of sodium eluted from the film>
A 20 × 20 mm resin-coated metal plate was immersed in 15 mL of boiled ultrapure water (specific resistance value ≧ 18.2 MΩ) for 10 seconds, then taken out and washed with water. Next, after diluting the eluted ultrapure water with a dilute acid, the amount of sodium was quantified by ICP mass spectrometry using ELAN DRC II manufactured by PerkinElmer.

<Coating film adhesion test>
After diluting lead / chrome-free rust preventive paint (OZ green primer for sash manufactured by Dai Nippon Toryo Co., Ltd.) with thinner (OZ green thinner manufactured by Dai Nippon Toryo Co., Ltd.) and adjusting the viscosity (20 seconds with Ford Cup # 4). The thinner was spray-coated on the resin-coated metal plate at a spray pressure of 0.4 MPa. Then, it was aged at room temperature for 1 week to prepare a coating material having a coating thickness of 30 to 40 μm. The following primary adhesion test and secondary adhesion test were performed on this coating material.
(Primary adhesion test)
Use a cutter knife to cut 100 squares of 1 mm square grid on the painted surface of the above-mentioned coating material, and perform a tape peeling test on this painted surface (the tape used is "Cellotape (registered trademark) Part No. 405" manufactured by Nichiban Co., Ltd.). carried out. This tape peeling test was performed twice, and the coating film adhesion was evaluated according to the following criteria based on the average value of the number of remaining squares of the coating film.
⊚: Number of remaining squares is 98 squares or more ○: Number of remaining squares is 90 squares or more and less than 98 squares △: Number of remaining squares is 70 squares or more and less than 90 squares ×: Number of remaining squares is less than 70 squares

(Secondary adhesion test)
After immersing the above coating material in boiling water for 1 hour, taking it out, leaving it for 1 hour, cut 100 squares of 1 mm square grid on the painted surface with a cutter knife, and perform a tape peeling test on this painted surface (the tape used is Nichiban Co., Ltd. "Cellotape (registered trademark) product number No. 405") was carried out. This tape peeling test was performed twice, and the coating film adhesion was evaluated according to the following criteria based on the average value of the number of remaining squares of the coating film.
⊚: Number of remaining squares is 98 squares or more ○: Number of remaining squares is 90 squares or more and less than 98 squares △: Number of remaining squares is 70 squares or more and less than 90 squares ×: Number of remaining squares is less than 70 squares

<Salt water resistance test>
After sealing the back surface and edge of the coating material, make a cross cut with a cutter knife, immerse it in a sodium chloride aqueous solution (30 g / L) at a liquid temperature of 23 ° C ± 2 ° C for 96 hours, wash it with water, and then wash it on the front surface. The water was wiped off, and a tape peeling test of the cross-cut portion (the tape used was "Cellotape (registered trademark) Part No. 405" manufactured by Nichiban Co., Ltd.) was immediately carried out. For the coating material after the peeling test, the maximum peeling width on one side from the cross-cut portion was measured and evaluated according to the following criteria.
⊚: Peeling width less than 1.0 mm ◯: Peeling width 1.0 mm or more and less than 1.5 mm Δ: Peeling width 1.5 mm or more and less than 3.0 mm ×: Peeling width 3.0 mm or more

<Sliding test>
A 40 mm × 300 mm sample was cut out from a resin-coated metal plate, set vertically on a tensile tester, and a flat plate die (material: SKD11) was brought into contact with the back surface of the sample. Next, a jig (semi-cylindrical die, material: SKD11) having a convex portion with a tip radius R = 9.1 mm is brought into contact with the opposite surface (front surface) of the sample that comes into contact with the flat plate die, and the jig is brought into contact with 2940N (2940N). While applying a load of 300 kgf) in the horizontal direction, the jig was pulled downward at 300 mm / min within the range where the flat plate die was in contact with the back surface of the sample. Then, after separating the flat plate die from the sample and returning it to the position before sliding, the same sliding operation as described above was repeated 6 times (7 times in total). _{After that, the amount of film adhered to the portion (W 1} ) and the non-sliding portion (W ₀ ) on which the flat plate die was repeatedly slid was analyzed by a fluorescent X-ray analyzer, and the film residual rate was calculated from the following formula (1). Was calculated and evaluated according to the following criteria.
Film residual rate (%) = W ₁ / W ₀ x 100 ... (1)
⊚: Film residual rate 85% or more ○: Film residual rate 75% or more and less than 85% ×: Film residual rate less than 75%

The amount of the film adhered was calculated from the ratio of the Si element contained in the film based on the following formula (2) by analyzing the Si element of _{colloidal silica (SiO 2) contained in the film.} In addition, C in the following formula (2) is the ratio (mass%) _{of colloidal silica (SiO 2) in the film.}
Film adhesion amount (g / m ² ) = Si (mg / m ² ) x (60/28) x (100 / C) / 1000 ... (2)

(Preparation of resin aqueous liquid A)
626 parts of water, ethylene-acrylic acid copolymer (20% by mass of acrylic acid, melt index (MI) 300) in an autoclave (content capacity 0.8L) equipped with an emulsifying facility equipped with a stirrer, thermometer, and temperature controller. ) 160 parts was added, and 0.4 mol of triethylamine and 0.15 mol of sodium hydroxide were added to 1 mol of the carboxyl group of the ethylene-acrylic acid copolymer, and 3 at 150 ° C. and 0.5 MPa. After stirring at high speed for a time, it was cooled to 40 ° C. Then, in autoclave, 4,4'-bis (ethyleneiminocarbonylamino) diphenylmethane (Chemitite (registered trademark) manufactured by Nippon Catalytic Co., Ltd.) was applied as a cross-linking agent to 100 parts of the non-volatile resin component of the ethylene-acrylic acid copolymer. 5 parts of DZ-22E) was added and stirred for 10 minutes to obtain an aqueous dispersion (polyethylene resin aqueous solution) A in which the polyethylene resin was dispersed.

(Preparation of resin aqueous liquid B)
An ethylene-acrylic acid copolymer as an olefin-acid copolymer (“Primacol (registered trademark) 5990I” manufactured by Dow Chemical Co., Ltd., acrylic acid) in an autoclave equipped with an emulsifying facility equipped with a stirrer, a thermometer, and a temperature controller. Derived structural unit: 20%, mass average molecular weight (Mw): 20,000, melt index: 1300, acid value: 150) 200.0 parts, styrene-acrylic acid copolymer (Mw: about 7000 [polystyrene conversion]] ) 8.0 parts by mass, 35.5 parts of triethylamine (0.63 equivalent with respect to the carboxyl group of the ethylene-acrylic acid copolymer), 3.5 parts of tall oil fatty acid ("Hartall FA3" manufactured by Harima Kasei Co., Ltd.), 792.6 parts of ion-exchanged water was added and sealed, and the mixture was stirred at high speed for 3 hours at 150 ° C. and 0.5 MPa, and then cooled to 30 ° C. Next, 31.2 parts of a carbodiimide group-containing compound (“Carbodilite (registered trademark) SV-02” manufactured by Nisshinbo Chemical Co., Ltd., polycarbodiimide, Mw: 2,700, solid content 40%) and 72.8 parts of ion-exchanged water were added. Then, the mixture was stirred for 10 minutes to prepare an emulsion of the olefin-acid copolymer and the carboxylic acid polymer (solid content concentration: about 20%, measured according to JIS K 6833), and the polyethylene-based resin was dispersed. An aqueous dispersion (polyethylene resin aqueous solution) B was obtained.

(Preparation of resin aqueous liquid C)
An ethylene-acrylic acid copolymer as an olefin-acid copolymer in an autoclave with an internal capacity of 0.8 L equipped with an emulsifying facility equipped with a stirrer, a thermometer, and a temperature controller ("Primacol (registered trademark) manufactured by Dow Chemical Co., Ltd." ) 5990I ”, constituent unit derived from acrylic acid: 20%, mass average molecular weight (Mw): 20,000, melt index: 1300, acid value: 150) 200.0 parts, polymaleic acid aqueous solution as a carboxylic acid polymer (day) "Non-pole (registered trademark) PMA-50W" manufactured by Yusha, Mw: Approximately 1100 (polystyrene equivalent), 50% product) 8.0 parts, triethylamine 35.5 parts (relative to the carboxyl group of the ethylene-acrylic acid copolymer) 0.63 equivalent), 3.5 parts of tall oil fatty acid (“Hartall FA3” manufactured by Harima Kasei Co., Ltd.), and 792.6 parts of ion-exchanged water are added and sealed, and stirred at 150 ° C. and 0.5 MPa at high speed for 3 hours. Then, it was cooled to 30 ° C. Next, 10.4 parts of a glycidoxy group-containing silane coupling agent (“TSL8350” manufactured by Momentive Performance Materials (former company name: GE Toshiba Silicone), γ-glycidoxypropyltrimethoxysilane), a carbodiimide group-containing compound ( Add 31.2 parts of "carbodilite (registered trademark) SV-02" manufactured by Nisshinbo Chemical Co., Ltd., polycarbodiimide, Mw: 2,700, solid content 40%) and 72.8 parts of ion-exchanged water, and stir for 10 minutes. , An emulsion of an olefin-acid copolymer and a carboxylic acid polymer was prepared (solid content concentration: about 20%, measured according to JIS K 6833), and an aqueous dispersion (polyethylene) in which a polyethylene-based resin was dispersed. A water-based resin aqueous solution) C was obtained.

(Preparation of resin aqueous liquid D)
Polytetramethylene ether glycol (manufactured by Hodogaya Chemical Co., Ltd., number average molecular weight 1000) 60 g, 1, as a polyol component in an autoclave (content capacity 0.8 L) equipped with an emulsifying facility equipped with a stirrer, thermometer, and temperature controller. 14 g of 4-cyclohexanedimethanol and 20 g of dimethylolpropionic acid were charged, and 30.0 g of N-methylpyrrolidone was further added as a reaction solvent. 104 g of tolylene diisocyanate was charged as an isocyanate component, the temperature was raised to 80 to 85 ° C., and the reaction was carried out for 5 hours. The NCO content of the obtained prepolymer was 8.9%. Further, 16 g of triethylamine was added for neutralization, a mixed aqueous solution of 16 g of ethylenediamine and 480 g of water was added, emulsified at 50 ° C. for 4 hours, subjected to a chain extension reaction, and an aqueous dispersion D (an aqueous dispersion D in which a carboxyl group-containing polyurethane resin was dispersed) was dispersed. A non-volatile resin component of 29.1% and an acid value of 41.4) were obtained.

<Coroidal silica>
The following 7 types of colloidal silica were used, 3 types were used as the small particle size colloidal silica, and 4 types were used as the large particle size colloidal silica.
(Small particle size colloidal silica)
Ammonia-stabilized silica sol manufactured by Nissan Chemical Industries, Ltd. Snowtex (registered trademark) NXS (average particle size 4 to 6 nm (notarized value), solid content concentration 15%)
Snowtex (registered trademark) XS manufactured by Nissan Chemical Industries, Ltd., which is a sodium-stabilized silica sol (average particle size 4 to 6 nm (notarized value), solid content concentration 20%)
Snowtex (registered trademark) OXS manufactured by Nissan Chemical Industries, Ltd., which is an acidic sol (average particle size 4 to 6 nm (notarized value), solid content concentration 10%)
(Large particle size colloidal silica)
Ammonia-stabilized silica sol manufactured by Nissan Chemical Industries, Ltd. Snowtex (registered trademark) N30G (average particle size 10 to 15 nm (notarized value), solid content concentration 30%)
Snowtex (registered trademark) 40 manufactured by Nissan Chemical Industries, Ltd., which is a sodium-stabilized silica sol (average particle size 10 to 15 nm (notarized value), solid content concentration 40%)
Snowtex (registered trademark) 50 manufactured by Nissan Chemical Industries, Ltd., which is a sodium-stabilized silica sol (average particle size 20 to 25 nm (notarized value), solid content concentration 50%)
Snowtex (registered trademark) O manufactured by Nissan Chemical Industries, Ltd., which is an acidic sol (average particle size 10 to 15 nm (notarized value), solid content concentration 20%)
Regarding Snowtex (registered trademark) OXS and O, triethylamine (manufactured by Wako Pure Chemical Industries, Ltd.) is 0.7% of 100% of Snowtex (registered trademark) OXS, and 100% of Snowtex (registered trademark) O. 0.5% was added to% and used as amine-stabilized silica.

<Metavanadate>
The following two types of metavanadates were used.
Ammonium metavanadate (Ammonium metavanadin (V) manufactured by Wako Pure Chemical Industries, Ltd. (solid content concentration: about 99%))
Sodium metavanadate (manufactured by Shinko Kagaku Kogyo Co., Ltd., sodium metavanadate (solid content concentration: about 66%))

(No. 1-38)
<Preparation of surface treatment composition>
At least one of the above colloidal silicas was added to any of the resin aqueous liquids A to D, and the colloidal silica and the emulsion in the resin aqueous liquid were well mixed to prepare a mixed liquid. No. In 1 to 9, this mixed solution was used as a surface treatment composition. In addition, No. In Nos. 10 to 38, a glycidoxy group-containing silane coupling agent (KBM403 (solid content concentration 100%) manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the mixture, and if necessary, the metavanadate and acrylic modified epoxy resin (Arakawa) were added. Modelix (registered trademark) 302 (solid content concentration 33.5%) manufactured by Kagaku Kogyo Co., Ltd. was added to prepare a surface treatment composition. Table 1 shows the mixing ratio (mass%) of each component in the surface treatment composition. In addition, No. In 20 to 21, two types of colloidal silica having a small particle size are used, with Snowtex (registered trademark) NXS being 21% and Snowtex (registered trademark) XS being 11%. No. In 19 to 21, two types of colloidal silica having a large particle size are used, and No. In 19, Snowtex (registered trademark) N30G was 21%, Snowtex (registered trademark) 40 was 11%, and No. In 20 to 21, Snowtex (registered trademark) N30G is 16%, and Snowtex (registered trademark) 40 is 16%.

<Manufacturing of resin-coated metal plate>
As the metal plate, an alkali degreased cold-dip galvanized metal plate (GI) (Zn adhesion amount 45 g / m ² ) or an alloyed hot-dip galvanized metal plate (GA) (Zn adhesion amount 45 g / m ² ) is used. bottom. After applying the above surface treatment composition to the surface of this metal plate, excess treatment liquid is removed with a drawing roll, and the surface is heated and dried for about 12 seconds (Peek Metal Temperature (PMT) 90 ° C.). , A resin-coated metal plate having a resin film adhesion amount of 0.3 to 0.8 g / m ^{2 was produced.} Table 1 shows the evaluation results of the obtained resin-coated metal plate.

The resin-coated metal plate of the present invention can be made into a resin-coated metal plate having excellent slidability by providing a resin film obtained from a predetermined surface treatment composition. In addition, when the paint is post-coated on the resin-coated metal plate (especially when the resin-coated metal plate is coated with a harmful substance-free paint and dried at room temperature to cure), the coating has excellent salt water resistance and coating adhesion. It can be a resin-coated metal plate to be a plate. Therefore, the resin-coated metal plate of the present invention can be used for building materials and the like.

Claims (11)

A step of preparing a surface treatment composition containing colloidal silica, a resin component, and a liquid substance.
Of the total of 100 parts by mass of the colloidal silica and the resin component, the content of the colloidal silica is 30 to 80 parts by mass, and the content of colloidal silica having a particle size of less than 10 nm is 15 parts by mass. Mixing so that it exceeds
A step of preparing a surface treatment composition, which comprises stirring the blended colloidal silica, the resin component, and the liquid substance.
The step of applying the surface treatment composition to at least one surface of the metal plate, and
Wherein the surface treatment composition after curing by Drying method for producing a resin coated metal sheet comprising the steps of Ru cured by room temperature drying by applying a coating, the. The production method according to claim 1, wherein the obtained resin-coated metal plate elutes 4 mg / m ^{2 or less of sodium when immersed in deionized water at 100 ° C. for 10 seconds.} The production method according to claim 1 or 2, wherein the colloidal silica contains ammonia-stabilized colloidal silica. The surface treatment composition is alkaline and
The production method according to claim 3, further comprising a step of preparing the ammonia-stabilized colloidal silica by adding ammonia to the acidic type colloidal silica. The production method according to claim 1 or 2, wherein the stabilized colloidal silica contains an amine-stabilized colloidal silica. The surface treatment composition is alkaline and
The production method according to claim 5, further comprising a step of preparing the amine-stabilized colloidal silica by adding an amine to the acidic type colloidal silica. The production method according to any one of claims 1 to 6, wherein the colloidal silica is composed of a plurality of types of colloidal silica having different average particle sizes. The colloidal silica includes a first colloidal silica having an average particle diameter of 4 to 6 nm and a second colloidal silica having an average particle diameter of 10 to 15 nm.
The production method according to any one of claims 1 to 7, wherein the mixing ratio of the first colloidal silica and the second colloidal silica is 80:20 to 30:70 in mass ratio. The production method according to any one of claims 1 to 8, wherein the resin component contains an olefin-α, β-unsaturated carboxylic acid copolymer. The production method according to claim 9, wherein the resin component further contains an α, β-unsaturated carboxylic acid polymer. The production method according to any one of claims 1 to 10, wherein the liquid substance contains at least an organic solvent or water.