JP2016175400A - Resin-coated galvanized metal plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin-coated galvanized metal plate excellent in corrosion resistance, abrasion resistance and blackening resistance.SOLUTION: There is provided a resin-coated galvanized metal plate in which a first layer having a film thickness of 0.2 μm or more is laminated on at least one surface of a metal plate covered with a galvanized layer, and a second layer having a film thickness of 0.2 μm or more is laminated on the first layer, where the first layer is formed of a resin composition containing 70-95 mass% of a resin component and 5-30 mass% of colloidal silica in 100 mass% of the total of the resin component and the colloidal silica, and the second layer is formed of a resin composition containing 14-49.95 mass% of a resin component, 50-80 mass% of colloidal silica, and 0.05-6 mass% of a thixotropic agent in 100 mass% of the total of the resin component, the colloidal silica and the thixotropic agent.SELECTED DRAWING: None

Description

  TECHNICAL FIELD The present invention relates to a resin-coated galvanized metal plate used for a casing, interior part, exterior part, steel furniture, and other exterior plate materials and building materials of household electrical products.

  Conventionally, in electrical products, galvanized metal plates are often used for both exterior parts and interior parts, and among them, galvanized metal plates laminated with a resin coating with corrosion resistance are often used (for example, Patent Document 1). However, galvanization is relatively soft among metals, and the coating film with a high resin component content is also soft, so parts with such a coated metal plate may not be used as sliding parts. is there.

  On the other hand, as a method for imparting abrasion resistance to a coating film on the surface of a galvanized metal plate, a method of adding a large amount of a hard inorganic substance such as silica to the coating film as in Patent Document 2 is known. In particular, since silica is hard and has a rust-preventing action, it is often used as an inorganic substance added to the coating film on the surface of a metal plate.

JP 2007-269018 A JP 2000-248379 A

  However, when a large amount of an inorganic substance is added to the coating film, the film-forming property is deteriorated, so that the coating film easily passes moisture and the corrosion resistance is deteriorated. In addition, the galvanized metal plate has a phenomenon that the plating surface turns black under high temperature and high humidity. If the inorganic material is excessively added, the blackening resistance is also deteriorated. Therefore, when a large amount of hard inorganic material such as silica is added to the coating film, the coating film becomes hard, but the corrosion resistance and blackening resistance tend to deteriorate, and all of the wear resistance, corrosion resistance, and blackening resistance are provided. It cannot be a metal plate. For this reason, high-cost materials such as alloy plating of stainless steel and zinc with other metals have to be used for parts that require wear resistance.

  This invention is made | formed in view of the above situations, The objective is to provide the resin-coated galvanized metal plate excellent in corrosion resistance, abrasion resistance, and blackening resistance.

  The resin-coated galvanized metal plate of the present invention that has solved the above-mentioned problems is obtained by laminating a first layer containing a small amount of colloidal silica on the surface of a galvanized metal plate, and a thixotropic agent on the first layer. And a second layer containing a large amount of colloidal silica. Specifically, a first layer having a film thickness of 0.2 μm or more is laminated on at least one surface of a metal plate coated with a galvanized layer, and the film thickness is 0.2 μm or more on the first layer. A resin-coated galvanized metal plate in which a certain second layer is laminated, wherein the first layer has a resin component of 70 to 95% by mass and a colloidal silica of 5% in a total of 100% by mass of the resin component and colloidal silica. The second layer is composed of a resin component of 14 to 49.95% by mass and a colloidal of 100% by mass in total of the resin component, colloidal silica, and thixotropic agent. It is formed from a resin composition in which silica is 50 to 80% by mass and thixotropic agent is 0.05 to 6% by mass.

  The total film thickness of the first layer and the second layer is preferably 0.4 to 5 μm, and the total film thickness of the first layer and the second layer is 0.4 to 1.5 μm. More preferred.

  The resin composition forming the second layer preferably contains at least one of a polyolefin resin, a polyurethane resin, and a polyester resin.

  It is preferable that at least one of the crosslinking agent and the silane coupling agent is included in at least one of the resin compositions for forming the first layer and the second layer.

  According to the present invention, a predetermined resin layer is laminated on an inexpensive galvanized metal plate without using high-cost alloy plating or stainless steel, thereby being excellent in corrosion resistance, wear resistance, and blackening resistance. A resin-coated galvanized metal plate can be provided.

It is a photograph of the test material after the abrasion resistance test and having no sliding trace. It is a photograph of the test material after the abrasion resistance test and having a remarkable sliding mark.

  The resin-coated galvanized metal plate of the present invention (hereinafter sometimes simply referred to as “resin laminate”) has a first layer laminated on at least one surface of a metal plate coated with a galvanized layer. A resin-coated galvanized metal sheet having a second layer laminated thereon. The resin laminate of the present invention is a resin in which a first layer is laminated using a resin composition containing a small amount of colloidal silica, and a thixotropic agent and a large amount of colloidal silica are contained on the first layer. A second layer is laminated using the composition. Hereinafter, the resin laminate of the present invention will be described in detail.

[Metal plate]
The metal plate used in the present invention is not particularly limited as long as it is a galvanized metal plate. For example, hot-rolled raw sheet electrogalvanized metal sheet (EG), hot-rolled metal sheet electrogalvanized, cold-rolled original sheet, hot-dip galvanized metal sheet (GI), cold-rolled metal sheet, alloyed A hot dip galvanized metal plate (GA) etc. can be mentioned. Among these, an electrogalvanized metal plate (EG) is more preferable. This is because the electrogalvanized metal plate (EG) is suitable for exterior parts of electronic / electric equipment such as a back cover of a flat-screen television.

  The method of forming the electrogalvanized layer, hot-dip galvanized layer, or alloyed hot-dip galvanized layer on the metal plate is not particularly limited, and the conventional electrogalvanized treatment method, hot-dip galvanized treatment method, and further conventional methods Alloying methods can be employed. For example, in the case of producing an electrogalvanized metal plate, a method of conducting an electrogalvanizing process by energizing while being immersed in a zinc solution at 55 ° C. can be mentioned. When manufacturing a hot dip galvanized metal plate, the hot dip galvanization is performed by immersing it in a plating bath whose temperature is adjusted to about 430 to 500 ° C., and then cooled. Moreover, when manufacturing an alloying hot-dip galvanized metal plate, after the said hot-dip galvanization, after heating to the temperature of about 500-750 degreeC, alloying is performed and it is mentioned.

Also, the plating adhesion amount (per one side) is not particularly limited. For example, it is about 10 to 100 g / m ^{2 in} the case of an electrogalvanized metal plate, and about 10 to 100 g / m ^{2 in} the case of a hot dip galvanized metal plate. Can be mentioned.

  The metal plate may have a base layer formed in advance on at least one surface by base processing. For example, if the surface of the metal plate on the side where the first layer and the second layer are to be formed has a chemical conversion film layer (underlayer) formed by undertreatment, the adhesion between the metal plate and the first layer is improved. .

  Examples of the chemical film layer (underlying layer) include an organic film layer, an inorganic film layer, a phosphate film layer, and a chromate film layer. Among these, an organic film layer, an inorganic film layer, and a phosphate film layer are preferable. . As the organic coating layer, for example, a polyolefin resin, an epoxy resin, a polyacrylic resin, a polyurethane resin, a polyester resin, a fluorine resin, and a mixture, copolymer, modified resin, and the like are appropriately selected and used. do it. In addition, silica gel, colloidal silica, etc. may be added to the organic film for the purpose of improving corrosion resistance, trace amounts of various wax components may be added for the purpose of improving processability after coating, or coating film adhesion may be improved. For the purpose, a silane coupling agent may be added. Examples of the inorganic coating layer include a silicate coating layer, and phosphoric acid or fluoride may be added to the silicate coating.

The amount of adhesion of the chemical conversion film layer (undercoat layer) is not particularly specified. However, for example, in the case of an organic film layer or an inorganic film layer, the dry mass is preferably 10 mg / m ² or more in terms of corrosion resistance. . However, if it exceeds 50 mg / m ² , the effect of improving the corrosion resistance is saturated and the manufacturing cost increases.

[First layer]
The first layer is formed from a resin composition containing a resin component and colloidal silica (hereinafter referred to as a first layer forming resin composition).

<Resin component>
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, and a mixed or modified resin thereof are used as appropriate. It can be used alone or in combination of two or more. Among them, the inclusion of at least one of a polyolefin-based resin, a polyurethane-based resin, and a polyester-based resin is preferable from the viewpoint that excellent liquid stability can be obtained, and a polyolefin-based resin is more preferable. More preferably.

  In the first layer, the resin component is 70 to 95% by mass, preferably 75 to 90% by mass, in a total of 100% by mass of the resin component and colloidal silica. If it is out of the above range, the corrosion resistance and blackening resistance may be lowered.

(Polyolefin resin)
The polyolefin resin used in the present invention is not particularly limited, but the polyolefin resin is an olefin-α, β-unsaturated carboxylic acid copolymer (hereinafter sometimes referred to as “olefin-acid copolymer”). It is preferable to include. The olefin-acid copolymer improves the corrosion resistance.

  The “olefin-acid copolymer” in the present invention is a copolymer of an olefin and an α, β-unsaturated carboxylic acid, and the olefin-derived structural unit is 50% by mass in the copolymer. This means the above (ie, the structural unit derived from α, β-unsaturated carboxylic acid is 50% by mass or less).

(Olefin-α, β-unsaturated carboxylic acid copolymer)
The olefin-acid copolymer can be produced by copolymerizing an olefin and an α, β-unsaturated carboxylic acid by a known method, and is commercially available. 1 type (s) or 2 or more types can be used for an olefin-acid copolymer.

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

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

  The α, β-unsaturated carboxylic acid unit in the olefin-acid copolymer serves to improve the adhesion to the adjacent resin layer or metal plate, and in order to effectively exhibit such action. The amount of α, β-unsaturated carboxylic acid units in the copolymer is preferably 5% by mass or more, and more preferably 10% by mass or more. On the other hand, the upper limit of the amount of α, β-unsaturated carboxylic acid units in the copolymer is 50% by mass as described above, but is preferably 30% by mass or less, more preferably 25% by mass from the viewpoint of corrosion resistance. % Or less.

  The olefin-acid copolymer may have a constitutional unit derived from another monomer as long as it does not adversely affect the secondary aggregation of colloidal silica. 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 acid. A preferred olefin-acid copolymer is an ethylene-acrylic acid copolymer.

  The weight average molecular weight (Mw) of the olefin-acid copolymer is preferably from 1,000 to 100,000, more preferably from 3,000 to 70,000, and even more preferably from 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 resin used in the present invention may be composed of an olefin-acid copolymer and an α, β-unsaturated carboxylic acid polymer (hereinafter sometimes referred to as “carboxylic acid polymer”). preferable. The olefin-acid copolymer and the carboxylic acid polymer improve the corrosion resistance.

  The “carboxylic acid polymer” in the present invention is a polymer (including a copolymer) obtained by polymerization using α, β-unsaturated carboxylic acid as a monomer, and α, β- It means that the constituent unit derived from unsaturated carboxylic acid is 90% by mass or more in the polymer.

  Examples of the carboxylic acid polymer include homopolymers or copolymers of one or more α, β-unsaturated carboxylic acids, or copolymers obtained by copolymerizing other monomers (excluding olefins). A polymer is mentioned. Such carboxylic acid polymers can be produced by known methods and are commercially available. A carboxylic acid polymer can use 1 type (s) or 2 or more types.

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

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

  Preferred carboxylic acid polymers include, for example, polyacrylic acid, polymethacrylic acid, acrylic acid-maleic acid copolymer, polymaleic acid, etc. Among these, adhesion between adjacent resin layers and metal plates, etc. From the viewpoint, polymaleic acid is more preferable. Since polymaleic acid has a large amount of carboxyl groups, the adhesion with the adjacent resin layer or metal plate is further 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. , 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-based resin is preferably 1,000: 1 to 10: 1, more preferably 200: 1 to 20: 1, and further Preferably it is 100: 1 to 25: 1. If the content ratio of the carboxylic acid polymer is too low, the combined effect of the olefin-acid copolymer and the carboxylic acid polymer may not be sufficiently exerted. Conversely, the content ratio of the carboxylic acid polymer is excessive. Then, the olefin-acid copolymer and the carboxylic acid polymer may be phase-separated in the composition, and the resin layer may not be formed uniformly.

<Colloidal silica>
The resin composition for forming a first layer contains colloidal silica. Colloidal silica (solid content) is contained in a total of 100% by mass of the resin component and colloidal silica in an amount of 5% by mass or more (more preferably 10% by mass or more) and 30% by mass or less (more preferably 20% by mass or less). . If the colloidal silica content is outside the above range, the corrosion resistance and blackening resistance of the resin laminate may be reduced. The reason why the corrosion resistance and blackening resistance of the resin laminate are improved is presumed to be that colloidal silica is dissolved and eluted in a corrosive environment, resulting in a pH buffering action and a passive film forming action. Furthermore, by containing colloidal silica, it is possible to prevent the occurrence of a site (repel portion) where the first layer does not exist when the first layer-forming resin composition is applied and dried.

  Although it does not specifically limit as colloidal silica, Colloidal silica with a particle diameter of 4-20 nm is preferable from a viewpoint of the dispersibility in the resin composition for 1st layer formation, a corrosion resistance improvement effect, etc., and is concrete. The colloidal silica having a particle diameter of 4 to 6 nm (commercially available product is “Snowtex (registered trademark) XS” manufactured by Nissan Chemical Industries, Ltd.) and the colloidal silica having a particle diameter of 8 to 11 nm (commercially available product is Nissan Chemical Industries, Ltd.). "Snowtex (registered trademark) S"), colloidal silica having a particle size of 10 to 20 nm (commercially available product, "Snowtex (registered trademark) 40" manufactured by Nissan Chemical Industries, Ltd.) and the like. “Snowtex (registered trademark) XS” is particularly preferable.

<Crosslinking agent>
In order to crosslink the resin, a crosslinking agent may be added to the resin composition for forming the first layer. By including a cross-linking agent, the corrosion resistance of the resin laminate can be enhanced. The crosslinking agent is preferably 0.5 to 10% by mass and more preferably 1 to 5% by mass in 100% by mass of the total solid content of the resin composition for forming the first layer. In the present specification, the total solid content means the total solid content of the resin component, colloidal silica, thixotropic agent, silane coupling agent, and crosslinking agent.

  The crosslinking agent is preferably an epoxy-based crosslinking agent from the viewpoint of reactivity, and sorbitol polyglycidyl ether, (poly) glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, Examples include polyglycidyl ethers such as (poly) ethylene glycol diglycidyl ether, and polyglycidyl amines. As such an epoxy-based crosslinking agent, Epicron (registered trademark) CR75, CR5L, and the like manufactured by DIC are available.

<Silane coupling agent>
A silane coupling agent may be added to the first layer forming resin composition. By including a silane coupling agent, the corrosion resistance of the resin laminate, the adhesion between the first layer and the metal plate, and the adhesion between the second layer and the first layer can be enhanced. As the silane coupling agent, a silane coupling agent having a glycidoxy group at the terminal is preferable. For example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, vinyltris (β-methoxyethoxy) Silane etc. are mentioned. A commercially available product may be used as the silane coupling agent, and examples thereof include γ-glycidoxypropyltrimethoxysilane “KBM403” (manufactured by Shin-Etsu Chemical Co., Ltd.).

  The content of the silane coupling agent is preferably 1 to 10% by mass and more preferably 2 to 5% by mass in 100% by mass of the total solid content of the resin composition for forming the first layer. When the content of the silane coupling agent is less than 1% by mass, the corrosion resistance of the resin laminate, the adhesion between the first layer and the metal plate, and the adhesion between the second layer and the first layer may be reduced. is there. On the other hand, if the content of the silane coupling agent exceeds 10% by mass, the effect of improving the corrosion resistance of the resin laminate, the adhesion between the first layer and the metal plate, and the adhesion between the second layer and the first layer is saturated. Tend to.

(Film thickness of the first layer)
The first layer can be formed by applying the first layer forming resin composition to a predetermined dry film thickness on one side or both sides of the metal plate described above and drying it. The film thickness of the first layer is 0.2 μm or more in dry film thickness, preferably 0.3 μm or more, more preferably 0.4 μm or more, particularly preferably 0.6 μm or more, and most preferably 1 μm. It is above, Preferably it is 4 micrometers or less, More preferably, it is 3.5 micrometers or less, More preferably, it is 3 micrometers or less, Most preferably, it is 2 micrometers or less. When the film thickness is less than 0.2 μm, the corrosion resistance decreases. When the film thickness exceeds 4 μm, the corrosion resistance, abrasion resistance, and blackening resistance are excellent, but it is difficult to obtain a further improvement effect, while the time required for coating and drying becomes long and the manufacturing cost increases.

[Second layer]
The second layer is formed from a resin composition containing a resin component, colloidal silica, and a thixotropic agent (hereinafter referred to as a second layer forming resin composition).

<Resin component>
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, and a mixed or modified resin thereof are used as appropriate. It can be used alone or in combination of two or more. Among these, polyolefin resins, polyurethane resins, and polyester resins are preferable in that excellent liquid stability can be obtained.

  In the second layer, the resin component is 14 to 49.95% by mass, and preferably 20 to 35% by mass, in a total of 100% by mass of the resin component, colloidal silica, and thixotropic agent. If it is less than 14% by mass, the corrosion resistance may be reduced. Moreover, when it exceeds 49.95 mass%, there exists a possibility that abrasion resistance may fall.

(Polyolefin resin)
The polyolefin resin used in the second layer is not particularly limited, but the polyolefin resin used in the second layer may be the same as or different from the resin used in the first layer. It is preferably the same as the resin used in one layer. The preferred polyolefin resin is the same as the polyolefin resin added to the first layer forming resin composition.

(Polyurethane resin)
Although it does not specifically limit as a polyurethane-type resin used by a 2nd layer, It is preferable that it is resin obtained by making a polyol and polyisocyanate react. Here, each of the polyol and polyisocyanate may be one kind or two or more kinds, and the polyurethane resin itself may be only one kind or two or more kinds.

The polyol is not particularly limited as long as it has two or more hydroxyl groups (hydroxy groups) in the molecule, and examples thereof include polyacryl polyol, polyester polyol, and polyether polyol.
Examples of the polyacryl polyol include a copolymer of a (meth) acrylic acid ester monomer and a monomer having a hydroxyl group. Here, examples of the (meth) acrylate monomer include methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. (Meth) acrylic acid hydroxyalkyl esters such as 4-hydroxybutyl (meth) acrylate and 2-hydroxypentyl (meth) acrylate; (meth) acrylic acid monoesters of polyhydric alcohols such as glycerin and trimethylolpropane; N-methylol (meth) acrylamide; In addition to the (meth) acrylic acid ester monomer and the monomer having a hydroxyl group, the polyacryl polyol may be a copolymer obtained by copolymerizing another monomer. ) Unsaturated monocarboxylic acids such as acrylic acid; unsaturated dicarboxylic acids such as maleic acid and anhydrides and mono- or diesters thereof; unsaturated nitriles such as (meth) acrylonitrile; (meth) acrylamide, N-methylol (meta ) Unsaturated amides such as acrylamide; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether; α-olefins such as ethylene and propylene; Halogenated α and β such as vinyl chloride and vinylidene chloride -Unsaturated aliphatic monomer; α such as styrene, α-methylstyrene , Β-unsaturated aromatic monomers and the like can be copolymerized.

  As said polyester polyol, what is obtained by reaction of a polybasic acid component and a polyol component is mentioned, for example. Here, examples of the polybasic acid component include orthophthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetrahydrophthalate. Aromatic dicarboxylic acids such as acids; oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, tartaric acid, alkyl Aliphatic dicarboxylic acids such as succinic acid, linolenic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid; hexahydrophthalic acid, tetrahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid Fats such as acids Wherein the dicarboxylic acid; or their anhydrides, reactive derivatives such as alkyl esters, acid halides; can be used. Examples of the polyol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, and 1,6-hexane. Diol, 1,8-octanediol, 1,10-decanediol, 1-methyl-1,3-butylene glycol, 2-methyl-1,3-butylene glycol, 1-methyl-1,4-pentylene glycol, 2-methyl-1,4-pentylene glycol, 1,2-dimethyl-neopentyl glycol, 2,3-dimethyl-neopentyl glycol, 1-methyl-1,5-pentylene glycol, 2-methyl-1, 5-pentylene glycol, 3-methyl-1,5-pentylene glycol, 1,2-dimethylbuty Glycol, 1,3-dimethylbutylene glycol, 2,3-dimethylbutylene glycol, 1,4-dimethylbutylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, 1,4-cyclohexanedimethanol 1,4-cyclohexanediol, bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, and the like can be used.

  The polyether polyol can be obtained, for example, by adding an alkylene oxide to a polyhydric alcohol by ring-opening polymerization. Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, and trimethylolpropane. Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, and tetrahydrofuran.

  Examples of the polyisocyanate include tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,4-butane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and lysine. Aliphatic diisocyanates such as diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate; isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-cyclohexylmethane diisocyanate, 1,4 -Fats such as cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane Group diisocyanate; tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzyldiisocyanate, Aromatic diisocyanates such as 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate; dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α, α, α, α-tetramethyl Araliphatic diisocyanates such as xylylene diisocyanate; and the like.

  Furthermore, the polyurethane resin may be obtained by reacting a polyol and a polyisocyanate with another polyol or a chain extender. Examples of other polyols include sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, and trimethylol. Examples thereof include polyols having three or more hydroxyl groups such as ethane, trimethylolpropane and pentaerythritol. Examples of the chain extender include dihydroxycarboxylic acids such as dialkyrol alkanoic acids (for example, dimethylolacetic acid, dimethylolbutanoic acid, dimethylolpropionic acid, dimethylolbutyric acid, dimethylolpentanoic acid, etc.); dihydroxysuccinic acid; ethylene Glycols such as glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 1,6-hexanediol, propylene glycol; Aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, 1,4-butanediamine, aminoethylethanolamine; isophoronediamine, 4,4′-dicyclohexylmethanedia Alicyclic diamines such emissions; xylylenediamine, aromatic diamines such as tolylenediamine; and the like.

For the reaction for obtaining the polyurethane-based resin, a known method may be appropriately employed. For example, a one-shot method in which each component is reacted at a time or a multistage method in which the components are reacted stepwise can be employed. Moreover, what is necessary is just to set suitably also about the usage-amount ratio of each component at the time of obtaining a polyurethane-type resin.
The molecular weight of the polyurethane resin is not particularly limited. For example, the number average molecular weight is preferably 5,000 to 600,000, and more preferably 10,000 to 400,000.

  The polyurethane resin is preferably used as an aqueous dispersion. By doing so, it is possible to avoid the risk of explosions due to the use of organic solvents and the burden on the environment and the human body. The aqueous dispersion of polyurethane resin is typically an emulsion of polyurethane resin particles. Examples of the aqueous solvent used as a dispersion medium include water or water and hydrophilic organic solvents (for example, alcohol solvents such as methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol; ethyl acetate, butyl acetate, γ-butyrolactone, etc. A mixed solvent with an ester solvent; a ketone solvent such as acetone; an ether solvent such as tetrahydrofuran or dioxane; an aprotic polar solvent such as N-methylpyrrolidone; etc. can be used, but water is particularly preferable. When a mixed solvent of water and a hydrophilic organic solvent is used, the content ratio of the hydrophilic organic solvent is preferably 50% by mass or less, more preferably 30% by mass or less, and further preferably 10% by mass in the mixed solvent. % Or less.

  When the polyurethane resin is used as an aqueous dispersion, a neutralizing agent can be contained in the dispersion for the purpose of improving the stability of the polyurethane resin in the aqueous dispersion medium. Examples of the neutralizing agent include ammonia, N-methylmorpholine, triethylamine, dimethylethanolamine, methyldiethanolamine, triethanolamine, morpholine, tripropylamine, ethanolamine, triisopropanolamine, 2-amino-2-methyl-1 -Propanol etc. are mentioned.

  As the aqueous dispersion of polyurethane resin, commercially available products may be used. For example, Takelac (registered trademark) series (WS-4000, etc.) manufactured by Mitsui Chemicals Polyurethane, Adekabon titer (registered trademark) series manufactured by ADEKA (HUX-550, HUX-541, HUX-522, etc.), Superflex (registered trademark) series (SF170, etc.) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. and the like. You may use combining more than a seed.

(Polyester resin)
The polyester resin used in the second layer is not particularly limited, but is preferably an aqueous dispersion in which the polyester resin is dispersed in an aqueous medium (hereinafter referred to as water-dispersed polyester resin). The water-dispersed polyester resin is an aqueous dispersion in which a polyester resin is dispersed in an aqueous medium, and the polyester resin constituting the water-dispersed polyester resin is obtained by polycondensation of polyvalent carboxylic acid and glycol. Is.

  As the polyvalent carboxylic acid component constituting the polyester resin, aromatic, aliphatic or alicyclic dicarboxylic acids, trivalent or higher polyvalent carboxylic acids, or ester derivatives thereof can be used.

  Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bisphenoxy Ethane-p, p′-dicarboxylic acid, phenylindanedicarboxylic acid and the like, and ester-forming derivatives thereof can be used.

  Examples of the aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and the like, and ester-forming derivatives thereof can be used.

  Examples of the glycol component constituting the polyester resin include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5- Pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,4-dimethyl-2-ethylhexane-1 , 3-diol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol, , 2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol, Bisphenol A, 4,4′-methylenediphenol, 4,4 ′-(2-norbornylidene) diphenol, 4,4′-dihydroxybiphenol, o-, m-, and p-dihydroxybenzene, 4,4′- Isopropylidenephenol, 4,4′-isopropylidenediol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol and the like can be used.

  In order to facilitate water dispersion of the polyester resin, a compound containing a carboxylic acid (salt) group, a compound containing a sulfonic acid (salt) group, a compound containing a phosphonic acid (salt) group, and the like are copolymerized. Also good.

  In the present invention, for example, a modified polyester copolymer such as a block copolymer or a graft copolymer modified with acrylic, urethane, epoxy, or the like can be used as the polyester resin.

  The preferred polyester resin is selected from terephthalic acid, isophthalic acid, sebacic acid, 5-sodium sulfoisophthalic acid as the acid component, and ethylene glycol, diethylene glycol, 1,4-butanediol, and neopentyl glycol as the glycol component. Examples thereof include copolymers using those.

  The said polyester-type resin can be manufactured with the following manufacturing methods. For example, a polyester resin in which the dicarboxylic acid component is composed of terephthalic acid, isophthalic acid, and 5-sodium sulfoisophthalic acid, and the glycol component is composed of ethylene glycol and neopentyl glycol will be described. These monomers are directly esterified. Or it can manufacture by the method etc. which are manufactured by the 1st step which transesterifies, and the 2nd step which carries out the polycondensation reaction of the reaction product of this 1st step. At this time, for example, alkali metal, alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, titanium compound, or the like can be used as the reaction catalyst.

  The number average molecular weight (Mn) of the polyester resin is preferably 10,000 to 20,000, more preferably 15,000 to 20,000 in terms of polystyrene.

  Moreover, the glass transition temperature (Tg) of the said polyester-type resin becomes like this. Preferably it is 40-70 degreeC, More preferably, it is 40-67 degreeC.

  A commercially available product may be used as the water-dispersed polyester-based resin, for example, “Vylonal (registered trademark) MD-1100”, “Vylonal (registered trademark) MD-1200”, “Vylonal (registered trademark) MD-” manufactured by Toyobo Co., Ltd. 1245 "etc., and the above resins may be used alone or in combination of two or more.

<Colloidal silica>
The second layer contains colloidal silica. In the second layer, the colloidal silica is 50% by mass or more (preferably 60% by mass or more) and 80% by mass or less (preferably 75% by mass or less) in a total of 100% by mass of the resin component, colloidal silica, and thixotropic agent. )include. If the colloidal silica content is less than 50% by mass, the wear resistance may be reduced. On the other hand, if the content of colloidal silica exceeds 80% by mass, the corrosion resistance may decrease. Moreover, when colloidal silica is contained, it can prevent that the site | part (repel part) where a 2nd layer does not exist at the time of application | coating and drying of the resin composition for 2nd layer formation.

  Although it does not specifically limit as colloidal silica, Colloidal silica with a particle diameter of 4-20 nm is preferable from viewpoints of the dispersibility in the resin composition for 2nd layer formation, a corrosion-resistant improvement effect, etc., and is concrete. The colloidal silica having a particle diameter of 4 to 6 nm (commercially available product is “Snowtex (registered trademark) XS” manufactured by Nissan Chemical Industries, Ltd.) and the colloidal silica having a particle diameter of 8 to 11 nm (commercially available product is Nissan Chemical Industries, Ltd.). "Snowtex (registered trademark) S"), colloidal silica having a particle size of 10 to 20 nm (commercially available product, "Snowtex (registered trademark) 40" manufactured by Nissan Chemical Industries, Ltd.) and the like. “Snowtex (registered trademark) XS” is particularly preferable.

<Thixotropic agent>
The second layer contains a thixotropic agent. Examples of thixotropic agents include fillers such as bentonite, calcium carbonate, kaolin, and clay, polymerized linseed oil, castor oil wax, polyolefin, silica gel, aluminum organic acid salt, cellulose, amide waxes, and polyamide-based thixotropic agents described below. Can be used.

  The thixotropic agent is preferably a polyamide thixotropic agent (polyamideamine salt). The polyamide thixotropic agent is obtained by reacting a dicarboxylic acid and a diamine, but is not particularly limited as long as it is a thixotropic agent dispersible in the second layer forming resin composition. The polyamide thixotropic agent can be obtained, for example, from Enomoto Kasei Co., Ltd. as Disparon (registered trademark) AQ series. In the AQ series, a polyamide represented by the following chemical formula (R and R ′ are alkyl groups) is used as a main component, and the molecular weight of the polyamide in the AQ series is 3000 or less.

  Polyamide thixotropic agents form steric hindrance between particles by forming or adsorbing steric hindrance with thixotropic agents or with resin or colloidal silica in the paint by forming a three-dimensional network structure in the paint. It is considered that the fluidity suppressing effect of the resin composition is increased. This network structure consists of weak bonds such as van der Waals forces and hydrogen bonds that are easily broken by a certain amount of shearing force. The network structure is cut by the shearing force, but when left standing, the network structure is restored again. . Therefore, by adding thixotropic agent to the resin composition, thixotropy (thixotropic property) is developed, and the network structure is cut and the viscosity is lowered in the high shear rate region, and it is allowed to stand and have a low shear rate region. Then, the network structure is restored and the viscosity increases.

  The thixotropic agent may be 0.05% by mass or more and 6% by mass or less, and 0.1% by mass or more and 2% by mass or less in a total of 100% by mass of the resin component, colloidal silica, and thixotropic agent. preferable. If it is less than 0.05% by mass, the viscosity in the low shear rate region of the resin composition for forming the second layer will not be sufficiently high, so a wet film that is uniform immediately after coating is kept in a uniform state until after drying. This makes it difficult to cause the wet film to flow, and there is a possibility that a site (repel portion) where the second layer does not exist on the surface of the resin laminate is generated. On the other hand, when it exceeds 6 mass%, the effect of improving the appearance tends to be saturated.

<Crosslinking agent>
In order to crosslink the resin, a crosslinking agent may be added to the second layer forming resin composition. By including a cross-linking agent, the corrosion resistance of the resin laminate can be enhanced. About suitable content and a suitable crosslinking agent, it is the same as the crosslinking agent added to the resin composition for 1st layer formation.

<Silane coupling agent>
A silane coupling agent may be added to the second layer forming resin composition. By containing a silane coupling agent, the corrosion resistance of the resin laminate and the adhesion between the second layer and the first layer can be enhanced. About the suitable content and suitable silane coupling agent of a silane coupling agent, it is the same as the silane coupling agent added to the resin composition for 1st layer formation.

(Film thickness of the second layer)
A 2nd layer can be formed by apply | coating the resin composition for 2nd layer formation on a 1st layer so that it may become a predetermined dry film thickness, and making it dry. The film thickness of the second layer is 0.2 μm or more in terms of dry film thickness, preferably 0.4 μm or more, more preferably 0.6 μm or more, further preferably 1 μm or more, preferably 4 μm or less. More preferably, it is 3.5 μm or less, more preferably 3 μm or less, and most preferably 2 μm or less. If the film thickness is less than 0.2 μm, the wear resistance may be reduced. On the other hand, if the film thickness exceeds 4 μm, the corrosion resistance, abrasion resistance, and blackening resistance are excellent, but further improvement effects are difficult to obtain, while the time required for coating and drying becomes long and the manufacturing cost increases. Become.

[First layer and second layer]
The total film thickness of the first layer and the second layer is 0.4 μm or more in dry film thickness, more preferably 0.7 μm or more, further preferably 1 μm or more, preferably 5 μm or less, more preferably It is 4 μm or less, more preferably 3 μm or less. If the total film thickness exceeds 5 μm, the corrosion resistance, abrasion resistance, and blackening resistance are excellent, but further improvement effects are difficult to obtain, while the time required for painting and drying becomes long, and the manufacturing cost increases. . Further, if the total film thickness is too thick, for example, there may be a case where the conductivity required when used in the field of home appliances such as a flat-screen television cannot be achieved.

  In the case where high conductivity is required, the total film thickness of the first layer and the second layer is preferably 1.5 μm or less.

  It is preferable that at least one of a crosslinking agent and a silane coupling agent is included in at least one of the first layer forming resin composition and the second layer forming resin composition.

Hereinafter, the present invention will be described in detail based on examples. However, the following examples are not intended to limit the present invention, and all modifications made without departing from the spirit of the preceding and following descriptions are included in the technical scope of the present invention.
Hereinafter, “%” indicates “mass%”, and “part” indicates “part by mass”.

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

(1) Corrosion resistance About the test material (resin coating galvanized metal plate), the salt spray test based on JISZ2371 was implemented for 240 hours. Thereafter, the occurrence of white rust on the surface of the specimen was observed and evaluated according to the following criteria.
○: White rust generation rate is 20% or less ×: White rust generation rate exceeds 20%

(2) Abrasion resistance A Taber ablation tester manufactured by Yasuda Seiki Seisakusho was used. Specifically, a copy paper (COPY & LASER PAPER manufactured by APRIL Fine Paper) is wrapped around the wear ring, the load (self-weight) is 250 gf, and the wear ring is rotated by rotating the test material, thereby the wear resistance test. Went. The rotation speed of the wear wheel was 60 rpm, and the rotation speed of the wear wheel was 500 times. Then, it judged visually by the following reference | standard.
○: Minor or no trace on the appearance of the specimen (Fig. 1)
×: There is a noticeable sliding mark on the appearance of the specimen (Fig. 2)

(3) Blackening resistance First, L value of the test material was measured using a color difference meter (Nippon Denshoku Industries Co., Ltd. SZS-Σ90). And after storing the test material at 50 degreeC and the humidity 98% for 168 hours, L value of the test material was measured again. A difference ΔL between L values before and after storage for 168 hours was calculated and evaluated quantitatively.
○: ΔL is 1.5 or less ×: ΔL exceeds 1.5

(4) Appearance evaluation (evaluation of repellency of wet film)
Since the second layer is a clear coating film containing no color pigment, and the repellency part after drying cannot be visually determined, the evaluation was made with a wet film immediately after coating. In the test material, the coated surface excluding the edge portion of the A4 size test material was visually observed immediately after application of the second layer, and the occurrence state of the repellency portion was evaluated according to the following criteria.
○: Repelling part has occurred on the entire surface ×: Repelling part has not occurred

(5) Conductivity The electrical resistance value was measured by sliding the terminal on the surface of the test material using a tester and evaluated according to the following criteria.
◎: Less than 500Ω ○: 500Ω or more and less than 2000Ω Δ: 2000Ω or more

(Electrogalvanized metal plate)
As the metal plate, a galvanized metal plate, specifically, an electrogalvanized metal plate (EG) having a plate thickness of 0.8 mm and a zinc plating adhesion amount of 20 g / m ^{2 on} each side of the metal plate.
) Was used.

(Production method of aqueous polyolefin resin)
In an autoclave having an emulsification facility equipped with a stirrer, a thermometer, and a temperature controller, an ethylene-acrylic acid copolymer ("Primacol (registered trademark) 5990I" manufactured by Dow Chemical Co., Ltd., a structural 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 (“Nonpole (registered trademark) PMA-50W” manufactured by NOF Corporation), Mw: about 1100 ( (Polystyrene equivalent), 50% product) 8.0 parts, triethylamine 35.5 parts (0.63 equivalent to the carboxyl group of ethylene-acrylic acid copolymer), 6.9 parts of 48% NaOH aqueous solution (ethylene-acrylic) 1.5 equivalents of the carboxyl group of the acid copolymer), tall oil fatty acid ("Hartol FA3" manufactured by Harima Chemicals) 3.5 parts, and sealed with ion exchange water 792.6 parts, after 3 hours high speed stirring at 0.99 ° C. and 5 atm, and cooled to 30 ° C.. Next, 10.4 parts of a glycidoxy group-containing silane coupling agent (Momentive Performance Materials (former name: GE Toshiba Silicone) “TSL8350”, γ-glycidoxypropyltrimethoxysilane), carbodiimide group-containing compound ( “Carbodilite (registered trademark) SV-02” manufactured by Nisshinbo Chemical Co., Ltd., 31.2 parts of polycarbodiimide, Mw: 2,700, solid content 40%) and 72.8 parts of ion-exchanged water were added and stirred for 10 minutes. An emulsion (emulsion) of an olefin-acid copolymer and a carboxylic acid polymer was prepared (solid content concentration of about 20%, measured according to JIS K 6833), and an aqueous dispersion in which a polyolefin-based resin was dispersed (hereinafter referred to as “solid content concentration”) Polyolefin resin aqueous solution).

(About No. 1-40)
[Method for forming first layer]
Colloidal silica (Snowtex (registered trademark) XS manufactured by Nissan Chemical Industries, Ltd., solid content 20%) was added to the aqueous polyolefin resin liquid obtained above to prepare a resin composition for forming a first layer. The blending ratio of each component was blended so as to be 40 to 100 parts of polyolefin resin and 0 to 60 parts of colloidal silica in terms of solid content. This resin composition for forming a first layer is diluted with ion-exchanged water to adjust the solid content concentration to 10%, and stirred with a disper stirrer at 700 rpm × 10 minutes. It apply | coated so that it might become 08-2.59 micrometers, and it heat-dried at plate | board temperature 90-100 degreeC (furnace temperature 220 degreeC * 12 second), and formed the 1st layer on the EG original plate.

[Method for forming second layer]
The above-mentioned colloidal silica and polyamide thixotropic agent (Dispalon (registered trademark) AQ-607 manufactured by Enomoto Kasei Co., Ltd., solid content: 15%) are added to the aqueous polyolefin resin solution obtained above, and the resin composition for forming the second layer A product was made. The blending ratio of each component was blended so as to be 4.8 to 99.8 parts of polyolefin resin, 0 to 95 parts of colloidal silica, and 0.2 part of polyamide thixotropic agent in terms of solid content. This resin composition for forming the second layer is diluted with ion-exchanged water to adjust the solid content concentration to 10%, stirred with a disper stirrer at 700 rpm × 10 minutes, and then coated with a bar coater on the first layer with a film thickness of 0. The film was applied to a thickness of 0.05 to 2.02 μm, and dried by heating at a plate temperature of 90 to 100 ° C. (furnace temperature 220 ° C. × 12 seconds) to form a second layer on the first layer.

(About No. 41)
[Method for forming first layer]
The said colloidal silica was added to the polyolefin resin aqueous liquid obtained above, and the resin composition for 1st layer formation was produced. The blending ratio of each component was blended so as to be 85 parts of polyolefin resin and 15 parts of colloidal silica in terms of solid content. This resin composition for forming a first layer is diluted with ion-exchanged water to adjust the solid content concentration to 10%, and stirred with a disper stirrer at 700 rpm × 10 minutes. It apply | coated so that it might become 46 micrometers, and it heat-dried at plate | board temperature 90-100 degreeC (furnace temperature 220 degreeC * 12 second), and formed the 1st layer on EG original plate.

[Method for forming second layer]
The colloidal silica and the polyamide thixotropic agent are added to a polyurethane resin aqueous liquid (ADEKA BONTITER (registered trademark) HUX-522, solid content 30%, manufactured by ADEKA), and a resin composition for forming a second layer is obtained. Produced. The blending ratio of each component was blended so as to be 29.8 parts of polyurethane resin, 70 parts of colloidal silica and 0.2 part of polyamide thixotropic agent in terms of solid content. This resin composition for forming the second layer is diluted with ion-exchanged water to adjust the solid content concentration to 10%, stirred with a disper stirrer at 700 rpm × 10 minutes, and then coated with a bar coater on the first layer with a film thickness of 0. The film was applied to a thickness of .47 μm and dried by heating at a plate temperature of 90 to 100 ° C. (furnace temperature 220 ° C. × 12 seconds) to form a second layer on the first layer.

(About No. 42)
[Method for forming first layer]
No. on the galvanized metal plate. The first layer was formed in the same manner as in 41.

[Method for forming second layer]
The colloidal silica and the polyamide thixotropic agent were added to an aqueous polyester resin liquid (Vaironal (registered trademark) MD-1200 manufactured by Toyobo Co., Ltd., 34% solid content) to prepare a resin composition for forming a second layer. . The blending ratio of each component was blended so as to be 29.8 parts of polyester resin, 70 parts of colloidal silica, and 0.2 part of polyamide thixotropic agent in terms of solid content. This resin composition for forming the second layer is diluted with ion-exchanged water to adjust the solid content concentration to 10%, stirred with a disper stirrer at 700 rpm × 10 minutes, and then coated with a bar coater on the first layer with a film thickness of 0. The film was applied to a thickness of .47 μm and dried by heating at a plate temperature of 90 to 100 ° C. (furnace temperature 220 ° C. × 12 seconds) to form a second layer on the first layer.

(About No. 43-49)
[Method for forming first layer]
In order to the polyolefin resin aqueous solution obtained above, the colloidal silica, the epoxy-based crosslinking agent (Epiclon (registered trademark) CR75 manufactured by DIC), and the silane coupling agent (KBM403 manufactured by Shin-Etsu Chemical Co., Ltd., solid content 100%) sequentially. This was added to prepare a resin composition for forming a first layer. The blending ratio of each component was blended so as to be 79 to 85 parts of polyolefin resin, 15 parts of colloidal silica, 0 to 3 parts of epoxy crosslinking agent, and 0 to 3 parts of silane coupling agent in terms of solid content. This resin composition for forming a first layer is diluted with ion-exchanged water to adjust the solid content concentration to 10%, and stirred with a disper stirrer at 700 rpm × 10 minutes. It apply | coated so that it might become 36-0.46 micrometer, and it heat-dried at plate | board temperature 90-100 degreeC (furnace temperature 220 degreeC * 12 second), and formed the 1st layer on EG original plate.

[Method for forming second layer]
The colloidal silica, the epoxy crosslinking agent, the silane coupling agent, and the polyamide thixotropic agent were sequentially added to the polyolefin resin aqueous liquid obtained above to prepare a resin composition for forming a second layer. The blending ratio of each component is 23.8 to 29.8 parts of polyolefin resin, 70 parts of colloidal silica, 0 to 3 parts of epoxy crosslinking agent, 0 to 3 parts of silane coupling agent, polyamide thixotropic in terms of solid content. It mix | blended so that it might become 0.2 part of agent. This resin composition for forming the second layer is diluted with ion-exchanged water to adjust the solid content concentration to 10%, stirred with a disper stirrer at 700 rpm × 10 minutes, and then coated with a bar coater on the first layer with a film thickness of 0. The film was applied to a thickness of .36 to 0.47 μm and dried by heating at a plate temperature of 90 to 100 ° C. (furnace temperature 220 ° C. × 12 seconds) to form a second layer on the first layer.

(About No. 50)
[Method for forming first layer]
The said colloidal silica was added to the polyolefin resin aqueous liquid obtained above, and the resin composition for 1st layer formation was produced. The blending ratio of each component was blended so as to be 85 parts of polyolefin resin and 15 parts of colloidal silica in terms of solid content. This resin composition for forming a first layer is diluted with ion-exchanged water to adjust the solid content concentration to 10%, and stirred with a disper stirrer at 700 rpm × 10 minutes. It apply | coated so that it might become 30 micrometers, and it heat-dried at plate | board temperature 90-100 degreeC (furnace temperature 220 degreeC * 12 second), and formed the 1st layer on EG original plate.

[Method for forming second layer]
The colloidal silica was added to the aqueous polyolefin-based resin obtained above to prepare a resin composition for forming a second layer. The blending ratio of each component was blended so as to be 30 parts of polyolefin resin and 70 parts of colloidal silica in terms of solid content. This resin composition for forming the second layer is diluted with ion-exchanged water to adjust the solid content concentration to 10%, stirred with a disper stirrer at 700 rpm × 10 minutes, and then coated with a bar coater on the first layer with a film thickness of 0. It was applied to a thickness of .45 μm, and dried by heating at a plate temperature of 90 to 100 ° C. (furnace temperature 220 ° C. × 12 seconds) to form a second layer on the metal plate.

  The resin-coated galvanized metal plate of the present invention has a first layer laminated using a resin composition containing a small amount of colloidal silica, and a thixotropic agent and a large amount of colloidal silica are contained on the first layer. By laminating the second layer using the resin composition thus obtained, a resin-coated galvanized metal plate excellent in corrosion resistance, wear resistance, and blackening resistance can be obtained. Therefore, the resin-coated galvanized metal plate of the present invention can be used for casings and interior / exterior parts of household electrical products, outer plate materials such as steel furniture, building materials, and the like.

Claims (5)

A first layer containing a resin component and colloidal silica is laminated on at least one surface of a metal plate coated with a galvanized layer, and a resin component, colloidal silica, and a thixotropic agent are contained on the first layer. A resin-coated galvanized metal plate laminated with a second layer,
The first layer has a thickness of 0.2 μm or more, and the resin component is 70 to 95% by mass and the colloidal silica is 5 to 30% by mass in a total of 100% by mass of the resin component and colloidal silica.
The second layer has a film thickness of 0.2 μm or more, and the resin component is 14 to 49.95% by mass and the colloidal silica is 50 to 80 in a total of 100% by mass of the resin component, colloidal silica, and thixotropic agent. A resin-coated galvanized metal sheet, characterized in that the mass percentage is 0.05 to 6 mass%.   The resin-coated galvanized metal sheet according to claim 1, wherein the total film thickness of the first layer and the second layer is 0.4 to 5 µm.   The resin-coated galvanized metal sheet according to claim 1, wherein the total film thickness of the first layer and the second layer is 0.4 to 1.5 µm.   The resin-coated galvanized metal sheet according to any one of claims 1 to 3, wherein the second layer includes at least one of a polyolefin resin, a polyurethane resin, and a polyester resin.   The resin coating according to any one of claims 1 to 4, wherein at least one of a crosslinking agent and a silane coupling agent is included in at least one of the resin compositions for forming the first layer and the second layer. Galvanized metal plate.