WO2006080447A1

WO2006080447A1 - Precoated metal sheet and process for producing the same

Info

Publication number: WO2006080447A1
Application number: PCT/JP2006/301337
Authority: WO
Inventors: Nobuo Hattori
Original assignee: Kabushiki Kaisha Kobe Seiko Sho
Priority date: 2005-01-31
Filing date: 2006-01-27
Publication date: 2006-08-03
Also published as: TW200631674A; CN101124084B; TWI272135B; CN101124084A

Abstract

A precoated metal sheet which comprises a metal sheet and, formed on a surface thereof, a resin coating film comprising a fluororesin, wherein the concentration proportion of fluorine in an uppermost layer of the resin coating film, as calculated using the equation (1), is 20% or higher and the concentration proportion of fluorine in an inner layer located in a position about 1/2 the thickness of the coating film, as calculated using the following equation (1), is 15% or lower. A(%) = {F/(F+C+O+N)}×100 (1) (In the equation (1), A is the concentration proportion of fluorine; F is the amount of fluorine in mass%; C is the amount of carbon in mass%; O is the amount of oxygen in mass%; and N is the amount of nitrogen in mass%.)

Description

Specification

Pre-coated metal plate and manufacturing method thereof

Technical field

TECHNICAL FIELD [0001] The present invention relates to a precoated metal plate used for various uses such as an outer plate material such as a household electric product or an automotive on-vehicle component, as well as a building material or a roof material, and a method for manufacturing the same.

Background art

[0002] Metal thin plate materials typified by steel plates, aluminum plates or aluminum alloy plates are excellent in strength and workability, and can be processed variously for household electrical products, automotive components, and building materials. It is applied to various uses. The processed metal plate used for these applications may be subjected to surface treatment for the purpose of improving the appearance and corrosion resistance. Conventionally, the surface treatment has been mainly performed by post-coating after processing a metal plate into a specified shape. Recently, however, the purpose of this is to improve the work environment, simplify the machining process, and reduce costs. As a pre-coating method, a pre-coated metal plate that has been previously surface-treated on a metal plate is molded and molded into a predetermined shape. Furthermore, in recent years, such pre-coated metal sheets have various functions such as fingerprint resistance, scratch resistance, ground connection, heat dissipation, heat insulation, in order to meet the diversification of products and equipment and high quality. Functional pre-coated metal sheets with antibacterial properties have been developed and are widely used. In addition, in recent years, such pre-coated metal sheets have various functions such as fingerprint resistance, scratch resistance, ground connection, heat dissipation, Functional pre-coated metal sheets with heat shielding and antibacterial properties have been developed and are widely used.

[0003] Since the pre-coated metal sheet is formed with the surface coating applied, the appearance after press molding is kept as it is when the coating film is required to have excellent formability. In order to achieve a product appearance, excellent surface appearance and properties are required. For example, in Japanese Patent No. 3338156 (paragraph numbers 0008 to 0017), an aluminum alloy sheet is made of epoxy resin, urethane resin and acrylic resin alone or a mixture thereof, and the particle size Contains 5-40% SiO of 0.1 μm or less and 5-60% lubricant Disclosed is a pre-coated metal sheet that is coated with a thickness of 0.5 to: LO / zm and has excellent formability and scratch resistance with a friction coefficient controlled to 0.15 or less.

[0004] The pre-coated metal plate disclosed in Japanese Patent No. 3338156 (paragraph numbers 0008 to 0017) is composed of an aluminum alloy plate material. Generally, a pre-coated metal plate made of aluminum is light. For example, ECUs (Electronic Control Units), which are optical disc drive covers for laptop computers, liquid crystal display frames, back covers, and in-vehicle electrical components. It is also used for covers and structural members such as car stereos, car navigation systems, and disk auto changers. When used in an optical disk drive or autochanger, CDs and DVDs are loaded. Recently, with the widespread use of rewritable drives, it has become increasingly common to create personalized discs 10 by personally editing music CDs. Further, as shown in FIG. 4 (a), such a self-made disk 10 may be used in a state where an identification label L for identification is adhered to the surface of the disk D. Disclosure of the invention

[0005] However, in applications where an adhesive such as the identification label L may be inserted into the apparatus, such as the above-described optical disk drive or disk autochanger, the heat generated by the apparatus may cause Therefore, it is necessary to prepare for the risk that a part of the identification label L is peeled off and the exposed adhesive part Ln is then reattached to each part in the apparatus.

[0006] As one of the methods for preventing such a risk, it is effective to apply a surface treatment that makes it difficult for the adhesive (the identification label L) to adhere to the site where the adhesive (the identification label L) may adhere. Conceivable. For example, as shown in FIG. 4 (b), in the case of the optical disk drive 20, adjacent to the self-made optical disk 10 such as the upper surface of the tray 21 on which the self-made optical disk 10 is mounted and the inner surface of the cover 22 covering the self-made optical disk 10 However, it is considered that the larger the area, the greater the risk that the adhesive will adhere. Therefore, pre-coating metal plates used to cover these parts should be treated with a surface treatment to prevent sticking materials such as the identification label L from sticking. It is considered effective. In addition, these properties that are difficult to adhere are actually not only adhesives, but also repel various substances such as oil and dirt. Long-term use However, it is expected to reduce the frequency of maintenance.

[0007] In addition to the above-described problems, as shown in FIG. 4 (b), the conventional optical disk drive 20 has a tray 21 for setting the self-made optical disk 10 when the self-made optical disk 10 is put in and out. A drawer system that moves in and out of 20 was common.

[0008] On the other hand, although not shown in the drawing, the optical disc itself is inserted into the opening provided in the optical disc drive cover, although it is not shown in the figure, as described above. Such slot-in type optical disc drives have been developed. In such a slot-in type optical disk drive, the optical disk is inserted into and removed from the inner surface of the optical disk drive cover, so that the optical disk surface is rubbed against the inner surface of the optical disk drive cover when the optical disk is inserted and removed, and a sliding wrinkle occurs. There are problems with ease.

[0009] In order to prevent wrinkles on the surface of the optical disc when the optical disc is inserted and removed by a slot-in type optical disc drive, conventionally, a wrinkle prevention treatment is applied to a portion that is likely to slide with the optical disc by a technique such as spray coating. It is carried out. However, this method needs to be processed for each optical disc drive cover molded product after press calorie. For this reason, problems such as a complicated process, a decrease in productivity, and a very high cost have been pointed out. Therefore, it is expected that simplification of the process, improvement of productivity, and cost reduction will be realized by applying anti-wrinkle treatment to the aluminum plate before forming.

[0010] Therefore, in order to meet the above demand, the inventor of the present invention forms a resin film on the surface of a metal plate by applying and baking a fluorine-based paint combining a specific fluorine resin and a curing agent. By forming and optimizing the baking conditions, the fluorine concentration on the outermost surface of the resin film is increased to ensure the non-adhesiveness of the adhesive, and at the same time the fluorine concentration inside the film is reduced. We have devised a pre-coated metal sheet with excellent non-adhesive properties that maintains good adhesion between the metal sheet and the resin film and its manufacturing method.

[0011] The present invention is desirable for a pre-coated metal sheet to be used after being molded, and it is difficult to adhere to an adhesive even if it is used in an application that uses an adhesive that has excellent formability, lubricity, and appearance. A pre-coated metal sheet that has the characteristics of being hard to get oil and oil, and a method for manufacturing the same. [0012] The present invention is suitable for a pre-coated metal sheet that is molded and used, and in applications where an adhesive that has only excellent formability and appearance is used in combination, dirt and oil are difficult to adhere to. Furthermore, the present invention provides a precoated metal plate having a characteristic that the surface thereof is difficult to be scratched even when an optical disk or the like comes into contact, and a method for manufacturing the same.

[0013] In the first embodiment of the present invention, a pre-coated metal plate comprising a metal plate and a resin film made of fluorine-based resin formed on the surface thereof, the outermost surface of the resin film When the ratio of the fluorine concentration at the time is calculated by the formula (1), the ratio of the fluorine concentration is 20% or more, and the inside of the film of the resin film has a hook at a position of about 1Z2 of the film thickness. When the elemental concentration ratio is calculated by the formula (1), the fluorine concentration ratio is 15% or less.

A (%) = {F / (F + C + 0 + N)} X 100 (1)

In the formula (1), A is a ratio of fluorine concentration, F is fluorine mass%, C is carbon mass%, O is oxygen mass%, and N is nitrogen mass%.

[0014] With this configuration, the fluorine of the resin film is concentrated on the outermost surface, so that the peel strength of the adhesive in the resin film can be kept low. At the same time, since the fluorine concentration is kept low inside the film except the outermost surface, the resin film adheres firmly to the metal plate without forming a resin-based primer layer or adhesive layer. .

[0015] Further, the resin film comprises a fluorine-based resin having at least one of a hydroxyl group, a carboxyl group and an amino group and an isocyanate compound having two or more isocyanate groups, a urethane bond, an acid amide. A pre-coated metal plate is formed by bonding with at least one chemical bond among bonds and urea bonds. According to this structure, the fluorinated resin molecules form a three-dimensional network structure by cross-linking reaction due to these chemical bonds, so that the resin film adheres more firmly to the metal plate.

[0016] Further, the fluorinated resin has a molecular weight of 200,000 or less in terms of weight average molecular weight. With this configuration, the compatibility between the fluorine-based resin and the isocyanate compound having two or more isocyanate groups is improved, and the surface gloss of the obtained fluorine-based resin film is 60 ° specular. Gloss measurement exceeds 80, and an appearance with excellent gloss can be obtained. [0017] Further, the present invention is configured as a pre-coated metal plate having a corrosion-resistant film between the metal plate and the resin film. If comprised in this way, while the corrosion resistance of a precoat metal plate will improve, a resin film will adhere | attach the metal plate more firmly when.

[0018] The metal plate is configured as a pre-coated metal plate which is an aluminum plate or an aluminum alloy plate. If comprised in this way, weight reduction can be achieved compared with the case where another metal plate is used.

[0019] Further, in the method for manufacturing a precoated metal sheet according to the first embodiment, a first step of applying a fluorine-based paint to the surface of the metal sheet, and the fluorine-based paint is 200 ° C or more and 280 ° C. The following is a method for producing a precoated metal plate including a second step of baking to form a fluorinated resin film. With this configuration, the fluorine concentration of the resin film is concentrated on the outermost surface of the film by baking at a predetermined temperature, and can be kept low inside the film. Peel strength can be kept even lower. In addition, the resin film adheres more firmly to the metal plate.

[0020] In a second embodiment of the present invention, a pre-coated metal plate comprising a metal plate and a resin film formed on the surface thereof, wherein the resin film is a fluorine-based resin matrix layer and the fluorine film. A urethane bead dispersed in an elemental resin matrix layer, wherein the urethane beads content is 5% by mass or more and 50% by mass or less with respect to the fluorine resin matrix layer. Average particle size force of the urethane beads 1.1 times to 5 times the average thickness of the fluorine-based resin matrix layer, and the ratio of fluorine concentration on the outermost surface of the resin film is expressed by the formula (1 ), The ratio of the fluorine concentration is 15% or more, and the ratio of the fluorine concentration at the position of about 1Z2 of the film thickness inside the film of the resin film was calculated by the formula (1). When the ratio of the fluorine concentration is 15% or less Those configured as over preparative metal plate.

[0021] With such a configuration, even if an optical disk or the like comes into contact, the content and average particle diameter of urethane beads dispersed in the fluorine-based resin matrix layer (resin film) are controlled. Since urethane beads work as a cushioning material, it is possible to prevent wrinkles from entering the surface of an optical disk or the like by the resin film. Moreover, since the fluorine concentration on the surface of the resin film is concentrated on the outermost surface of the film, the peel strength of the adhesive to the resin film can be kept low. Also At the same time, since the fluorine concentration is kept low inside the film excluding the outermost surface of the film, the fluorine-based resin film adheres firmly to the metal plate even without forming a resin primer layer or adhesive layer. To do. Furthermore, since the average particle diameter is larger than the average thickness of the fluorine-based resin matrix layer V and urethane beads are included in the fluorine-based resin matrix layer, the surface of the resin film is a surface on which fine irregularities are formed. Thus, when the adhesive adheres to the resin film, a fine air layer is formed on the fine irregularities, and the contact area between the adhesive and the resin film decreases. As a result, the peel strength of the pressure-sensitive adhesive with respect to the resin film can be kept low.

[0022] Further, the fluorine-based resin matrix layer of the resin film has a fluorine-based resin having at least one of a hydroxyl group, a carboxyl group, and an amino group, and an isocyanate group having two or more isocyanate groups. This is a pre-coated metal plate in which the compound is bonded with at least one chemical bond of urethane bond, acid amide bond and urea bond.

[0023] With this configuration, the molecules of the fluorinated resin matrix layer form a three-dimensional network structure by cross-linking reaction due to these chemical bonds, so that the resin film is even stronger than the metal plate. Adhere to.

[0024] The urethane bead is configured as a precoated metal plate having an average particle size of 1.5 to 4 times the average thickness of the fluororesin matrix layer.

If comprised in this way, the effect | action as a cushion material of a urethane bead will improve, and it can further prevent that a wrinkle enters into the surface of an optical disk etc. by a sebum film.

[0025] Further, the urethane bead is configured as a pre-coated metal plate having a content of 10 to 40% by mass with respect to the fluorine-based resin matrix layer.

[0026] With this configuration, the action of the urethane beads as a cushioning material can be improved, and wrinkles can be further prevented from entering the surface of the optical disk or the like by the rosin film. In addition, when applying a fluorine-based paint in which urethane beads are dispersed on the surface of the metal plate to form a resin film, the viscosity of the fluorine-based paint is adjusted to a predetermined range, and the paintability is improved.

[0027] Further, it is configured as a pre-coated metal plate having a corrosion-resistant film between the metal plate and the resin film.

If comprised in this way, while the corrosion resistance of a precoat metal plate will improve, a resin film Adhere more firmly to the metal plate.

[0028] Further, the metal plate is configured as a pre-coated metal plate which is an aluminum plate or an aluminum alloy plate.

If comprised in this way, compared with the case where another metal plate is used, a light weight can be achieved.

[0029] Further, in the method for manufacturing a precoated metal sheet according to the second embodiment, a first step of applying a fluorine-based paint in which urethane beads are dispersed to the surface of the metal sheet; And a second step of forming the resin film by baking at a temperature not lower than 280 ° C and not higher than 280 ° C.

[0030] According to such a procedure, by the baking treatment at a predetermined temperature, the fluorine concentration in the resin film can be concentrated on the outermost surface of the film and can be kept low inside the resin film. The peel strength of the adhesive to the oil film can be kept low. In addition, the resin film adheres firmly to the metal plate. Furthermore, since urethane beads are fixed in the resin film and act as a cushioning material, it is possible to prevent wrinkles from entering the surface of an optical disk or the like.

[0031] In addition, according to the precoated metal sheet according to the first embodiment of the present invention, the precoated metal sheet used after being formed and processed by the fluorine-based resin film formed on the surface of the metal sheet. Even if it is used for applications that use adhesives that are desirable and have excellent moldability, lubricity, and appearance only, they can be combined with the characteristics that dirt and oil are difficult to adhere to, and the oil-based system. The fluororesin film can be strongly bonded to the metal plate without using a primer layer or an adhesive layer. In addition, the surface gloss can be controlled by controlling the molecular weight of the fluorinated resin that is the main component of the fluorinated paint.

[0032] In addition, according to the method for manufacturing a precoated metal sheet according to the first embodiment of the present invention, a precoated metal sheet having a low pressure-sensitive adhesive peel strength can be manufactured without forming a resin-based primer layer or an adhesive layer. Is done.

[0033] Furthermore, according to the pre-coated metal plate according to the second embodiment of the present invention, excellent molding that is desirable for a pre-coated metal plate that is molded and used by the resin film formed on the surface of the metal plate. Even if it is used for applications that use adhesives that are only adhesive and appearance, they can be combined with the property that they are difficult to adhere to dirt and oil, and they can be combined with a resin primer layer or adhesive layer. It is possible to bond the resin film firmly to the metal plate without The In addition, by optimizing the content and average particle size of the urethane beads dispersed in the resin film (fluorine-based resin matrix layer), it is possible to maintain the properties of preventing adhesion of adhesives to the resin film surface. Even when the oil film surface and the optical disk surface slide, the optical disk can be prevented from sticking.

[0034] Also, according to the method for producing a precoated metal sheet according to the second embodiment of the present invention, the precoated metal sheet having a small peel strength of the adhesive and excellent in preventing wrinkling to an optical disk or the like is a resin-based primer. Manufactured without the formation of layers or adhesive layers. In addition, by applying the anti-wrinkle treatment to the aluminum plate before the forming process in advance, the anti-wrinkle treatment can be performed with a simple process, high productivity and low cost compared to the case where the anti-wrinkle treatment is applied after the forming process. . Brief Description of Drawings

FIG. 1 (a) is a cross-sectional view schematically showing a configuration of a precoated metal sheet according to the first embodiment of the present invention, and FIG. 1 (b) is a second embodiment of the present invention. It is sectional drawing which shows typically the structure of the precoat metal plate which concerns on a form.

[Fig. 2] Fig. 2 is a photograph of an optical disc swatch that determines the anti-sticking property to the optical disc. (A) is a swatch sample with excellent anti-sticking property, and (b) is the anti-sticking property. A good sample.

[Fig. 3] Fig. 3 is a photograph of an optical disc swatch that determines the anti-sticking property to the optical disc. (A) is a swatch sample with slightly poor anti-sticking property, and (b) is an anti-sticking property photo. Is a bad sample.

[FIG. 4] FIG. 4 (a) is a perspective view schematically showing the configuration of a self-made disc and a state in which a part of the identification label is peeled off, and (b) is a perspective view schematically showing the configuration of the optical disc drive. It is a figure.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail.

First embodiment

[0037] 1. Pre-coated metal sheet

First, the configuration of the precoated metal sheet according to the first embodiment of the present invention will be described. The precoated metal plate la according to the first embodiment of the present invention has a base element as shown in FIG. A metal plate 2a which is a material, and a resin coating 3a which is formed on the surface of the metal plate 2a and is controlled so that the ratio of the fluorine concentration inside the coating and the inside of the coating becomes a predetermined value. Here, the surface of the metal plate 2a refers to at least one surface of the metal plate 2a, and preferably refers to both surfaces. Next, each configuration of the precoated metal plate la will be described.

[0038] (1) Metal plate

The metal plate 2a used in the first embodiment is not limited to the most common cold-rolled steel plate, but also hot-dip galvanized steel plate, electrogalvanized steel plate, galvannealed steel plate and copper-plated steel plate, All types of steel plates such as tin-plated steel plates, alloy steel plates such as stainless steel, aluminum or aluminum alloy plates, and non-ferrous metal plates such as copper or copper alloy plates are all applicable. Also, aluminum or aluminum alloy plates are preferred for applications where lightness is required, such as the power bar of an optical disk drive mounted on a notebook computer, the frame of a liquid crystal display device, and the cover of an in-vehicle electrical component. In particular, an Al—Mg alloy conforming to JIS 5052 and JIS 5182 is more preferable.

[0039] (2) Grease film

(2-1) Ratio of fluorine concentration

The precoated metal sheet la used in the first embodiment of the present invention has a fluorine concentration ratio of 20% or more on the outermost surface of the resin film 3a as calculated by the equation (1), and is the same. The ratio of the fluorine concentration inside the film of the resin film 3a when calculated by the formula (1) is 15% or less.

A (%) = {F / (F + C + 0 + N)} X 100 (1)

In the formula (1), A is a fluorine concentration ratio, F is fluorine mass%, C is carbon mass%, O is oxygen mass%, and N is nitrogen mass%.

In this case, the ratio of the fluorine concentration is calculated using ESCA or the like, converted into the formula using fluorine mass%, carbon mass%, oxygen mass% and nitrogen mass% inside the outermost surface of the resin film 3a and inside the film. Calculated in (1). The outermost surface of the film referred to here means the surface on the side to which the adhesive (identification label L shown in FIG. 4) adheres, that is, the outermost surface of the precoated metal plate lb. It does not refer to the interface with 2b. For the measurement inside the film, the film thickness is approximately 1 in the thickness direction from the outermost surface of the resin film 3a. Measure Z2 part. The measurement of the ratio of the fluorine concentration in the outermost surface of the resin film 3a and the inside of the film is explained in detail in (2-1) “Percentage of fluorine concentration” in the second embodiment. .

[0040] As shown in the comparative examples described later, when the crosslinking reaction of the resin film 3a is insufficient, thermal degradation

When (decomposition) occurs, the ratio of fluorine concentration on the outermost surface of the film may be less than 20%. In this case, since the proportion of fluorine present on the outermost surface of the resin film 3a is related to the peelability of the adhesive, the adhesive peel strength of the resin film 3a is increased, and dirt and oil are easily attached. Become. On the other hand, if the ratio of fluorine concentration inside the film exceeds 15%, the film will be firmly adhered to the surface of the metal plate la without taking measures such as forming a resin primer layer or an adhesive layer. I can't do that.

[0041] The resin film 3a is a fluorine-containing resin having at least one of a hydroxyl group, a carboxyl group and an amino group, and an isocyanate group having two or more isocyanate groups, preferably three or more isocyanate groups. The compound is preferably bonded (crosslinked) with at least one chemical bond among urethane bond, acid amide bond and urea bond. As a result, a stable cross-linked structure is formed in the resin film 3a, and the resin film 3a is more firmly bonded to the metal plate 2a. The above hydroxyl groups include, in a broad sense, derivatives that react with isocyanate groups as well as alcoholic hydroxyl groups and phenolic hydroxyl groups. The carboxyl group includes all derivatives that react with isocyanate groups, such as a carboxyl group alone and a dehydrated carboxyl group. Similarly, the amino group described above includes all derivatives that react with isocyanate groups. The degree of crosslinking of the crosslinked resin film 3a is preferably 80% or more in terms of the gel content defined in JIS K6796, which is an index of the degree of crosslinking.

[0042] (2-2) Molecular weight of fluorinated resin

The molecular weight of the fluorinated resin, which is the main component of the fluorinated paint, affects the surface gloss of the resin film 3a and, as a result, determines the surface gloss of the precoated metal sheet la. The surface gloss of the pre-coated metal sheet la according to the first embodiment may be either high gloss or low gloss (matte appearance). However, considering the use of outer sheet materials for household electrical products, etc. High gloss is preferred. The relationship between the molecular weight of fluorocarbon resin and surface gloss is Stated below.

[0043] When the molecular weight of the fluorinated resin is 200,000 or less in terms of weight average molecular weight, the main agent and the curing agent are uniformly compatible with each other, so that the resin film 3a having high gloss is obtained. In addition, when the molecular weight of the fluorocarbon resin, which is the main agent, exceeds 200,000 in terms of the weight average molecular weight, the compatibility between the main agent and the curing agent is lowered, and it is considered that a matte appearance is obtained. If the molecular weight of the fluorocarbon resin, which is the main agent, exceeds 200,000 in terms of the weight average molecular weight, the viscosity of the main agent becomes too high. When painting, the pick-up property of the paint is reduced and the glossiness of the surface is difficult to be uniform. In addition, when the molecular weight of the fluorocarbon resin, which is the main agent, is 100,000 or less in weight average molecular weight, the viscosity of the main agent becomes too low. For example, the resin film 3a is formed on the surface of the metal plate 2a by roll coating. When doing so, it may be difficult to maintain uniformity in film thickness.

[0044] (2-3) Thickness of the resin film: 0.1 to 20 m

The thickness of the resin film 3a according to the first embodiment is preferably 0.1-20111. When the thickness is less than 0.1 IX m, the entire surface of the metal plate 2a cannot be uniformly coated, and the peel strength of the adhesive increases. On the other hand, when the thickness exceeds 20 m, the adhesion to the metal plate 2a is lowered, and the adhesion of the resin film 3a to the metal plate 2a is lowered.

[0045] (2-4) Corrosion resistant coating

The precoated metal sheet la according to the first embodiment may further include a corrosion-resistant film between the metal plate 2a and the resin film 3a. The formation of the corrosion-resistant film imparts corrosion resistance to the pre-coated metal sheet la and improves the adhesion between the metal sheet 2a and the resin film 3b. The structure of the corrosion resistant film is, for example, as follows.

[0046] The corrosion-resistant film according to the first embodiment includes a conventionally known corrosion-resistant film containing Cr or Zr as a component, such as a phosphate chromate film, a chromate chromate film, a zirconium phosphate film, and an acid salt film. Zirconium-based coatings, coating-type chromate coatings, coating-type zirconium coatings, and the like can be used as appropriate. In addition, the adhesion amount of the corrosion-resistant film is preferably 10 to 50 mg / m ^{2 in} terms of Cr or Zr. If the adhesion amount of the corrosion-resistant film is less than 10 mg / m ^2, the entire surface of the metal plate 2a cannot be uniformly coated, and it becomes difficult to ensure the corrosion resistance, so that it cannot withstand long-term use. Further, when the deposition amount exceeds 50MgZm ^2, flop In less molding and the like, cracks (peeling) occur in the corrosion-resistant film, making it difficult to maintain high corrosion resistance over a long period of time.

[0047] 2. Method for producing pre-coated metal sheet

The manufacturing method of the pre-coated metal plate la according to the first embodiment includes a first step of applying a fluorine-based paint to the surface of the metal plate 2a and a baking treatment of the fluorine-based paint at 200 ° C or higher and 280 ° C or lower. And a second step of forming the fluorinated resin film 3a. Hereinafter, each process will be described.

[0048] (1) First step

The first step is a step of applying a fluorine-based paint to the surface of the metal plate 2a according to the first embodiment. This fluorine-based paint is an isocyanate compound having a fluorine resin having at least one of a hydroxyl group, a carboxyl group and an amino group as a main agent and two or more, preferably three or more isocyanate groups as a curing agent. More preferably, a mixture of blocked isocyanate compounds in which isocyanate groups are blocked is preferred. Further, a lubricant such as natural wax, petroleum wax, synthetic wax or a mixture thereof may be added to the fluorine-based paint. Furthermore, dyes and pigments for the purpose of coloring, additives such as various inorganic fillers and conductive additives for increasing the hardness resistance of the resin film 3a are within the scope of the claims of the present invention. It can be added without particular limitation.

[0049] The blocked isocyanate compound is a compound in which the active isocyanate group of the isocyanate compound is stabilized by a blocking agent such as an active hydrogen compound and is not reactive at room temperature. In this blocked isocyanate compound, the blocking agent is dissociated by heating such as baking, and the active isocyanate group is regenerated to have reactivity. Blocking agents for blocked isocyanate groups include alcohols such as methanol, ethanol, n-propanol and tert-butanol, phenols such as phenol, m-taresol, isooctylphenol and resorcinol, and ε-force. Examples include prolatatams, oximes, active methylene compounds such as acetylethylacetone, methylethylketone and ethylene chlorohydrin, and sodium sulfite. On the other hand, isocyanate compounds having blocked isocyanate groups include toluene diisocyanate, 4, 4 'dimethane methane diisocyanate (MDI), polymeric MDI, isophorone diisocyanate. And hexamethylene diisocyanate and the like. Polyisocyanates modified with polyhydric alcohols and polyisocyanates with burette bonds or isocyanate bonds are also included as isocyanate compounds.

[0050] In the fluorine-based paint using the blocked curing agent in this manner, since the isocyanate group of the curing agent is blocked at room temperature, the hydroxyl group, carboxyl group and amino group of the main agent and the isocyanate isocyanate of the curing agent. The reaction with the group (cross-linking reaction) does not proceed, and the fluorine paint is cured only by the baking process in the second step described later. Therefore, the fluorine-based paint can be stored for a long time in a state where the main agent and the curing agent are mixed, and the fluorine-based paint can be continuously applied to a long metal plate, which is industrially advantageous. It becomes.

[0051] The fluorine-based paint can be applied by any method such as brush, roll coater, curtain flow coater, roller curtain coater, electrostatic coating machine, blade coater, die coater, etc. It is more preferable to use a roll coater that is uniform and easy to work. The coating amount is such that the transport speed of the metal plate 2a, the rotation direction and the rotation speed of the roll coater, etc. so that the fluorine-based resin film 3a having a thickness of 0.1 to 20 / ζ πι is formed on the surface of the metal plate 2a. Is set as appropriate.

[0052] Prior to the application of the fluorine-based paint, a degreasing step of degreasing the surface of the metal plate 2a may be provided. For example, an aqueous alkali solution is sprayed on the surface of the metal plate 2a, and then washed with water to degrease the surface of the metal plate 2a. Furthermore, as described above, when a corrosion resistant film is provided between the metal plate 2a and the fluororesin film 3a, a chemical conversion treatment solution containing chromium ions or the like is applied to the surface of the metal plate 2a following the degreasing process. It is possible to form a corrosion-resistant film by spraying.

[0053] (2) Second step

This is a step of forming a fluorinated resin film 3a on the surface of the metal plate 2a according to the first embodiment, wherein the fluorinated paint applied in the first step is baked at 200 ° C or higher and 280 ° C or lower. Curing (crosslinking) the fluorine-based paint. Then, the fluorine paint cures (crosslinks) to form a fluorine resin film 3a in which the fluorine concentration ratio on the outermost surface of the film is 20% or more and the fluorine concentration ratio in the film is 15% or less. Is done. Fluorine-based resin film 3a Adheres firmly to the metal plate 2a. Here, the baking temperature is the peak temperature of the metal plate 2a.

[0054] When the baking temperature is less than 200 ° C, the fluorine-based paint is not sufficiently cured (cross-linked), and when the baking temperature exceeds 280 ° C, the fluorine-based paint is thermally deteriorated (decomposed). The concentration ratio cannot be set to a desired value, and the peel strength of the pressure-sensitive adhesive with respect to the surface of the fluorine-based resin film 3a increases. The baking time is preferably 20 to 60 seconds. If the treatment time is less than 20 seconds, baking will be insufficient, and if it exceeds 60 seconds, the baking treatment time will be too long and the productivity per hour will tend to decrease. The baking process is performed using, for example, a hot air furnace, an induction heating furnace, a near infrared furnace, a far infrared furnace, or an energy beam curing furnace.

Next, examples according to the first embodiment will be described in detail.

(Examples 1 to 5)

As Examples 1 to 5, precoated metal sheets la were produced according to the above production method. Each configuration of the pre-coated metal plate la is as follows.

(Metal plate)

An aluminum alloy plate conforming to JIS 5052—H34 was used with a thickness of 0.5 mm. (Corrosion resistant coating)

A phosphate chromate film was formed on both sides of the aluminum alloy plate. The amount of phosphate chromate film deposited was 20 mgZm ² in terms of Cr.

(Fluorine-based resin film)

Fluorine-based paint is applied to the outermost surface of the phosphate chromate film, and baking temperature (peak temperature of metal plate 2a) is 200, 220, 250, 260, 280. Baking treatment was performed with C to obtain a fluorine-based resin film having a film thickness of 5 m. Here, a fluorine-based paint in which the following two liquids were mixed was used as the fluorine-based paint.

(Main agent): Fluorine-based rosin having a hydroxyl group (weight average molecular weight: 176000).

(Curing agent): A blocked isocyanate compound having three isocyanate groups.

[0056] (Comparative Examples 1 to 7)

In Comparative Examples 1 to 4, precoated metal sheets la were produced in the same manner as in Examples 1 to 5 except that the baking was performed at 125, 150, 170, and 300 ° C. In Comparative Examples 5 and 6, the first embodiment A fluorine-based resin-coated aluminum plate was prepared using a different fluorine-based resin. The ETFE (ethylene tetrafluoroethylene) film used as the coating film (resin film) was strong enough that it could not be adhered to the aluminum plate surface as it was, so it was not possible to pass through a resin primer. The method of laminating ETFE film was selected. In Comparative Example 7, a precoated metal sheet la was produced in the same manner as in Example 3 except that an epoxy paint was used instead of the fluorine paint.

[0057] Next, with respect to the precoated metal sheet la of the precoated metal plates la of Examples 1 to 5 and Comparative Examples 1 to 7, the ratio of fluorine concentration in the outermost surface of the resin film 3a and the inside of the film, presence or absence of urethane bonds The results are shown in Table 1. The measurement method for each characteristic was as follows.

[0058] (Percentage of fluorine concentration)

The outermost surface and the inside of the film of the resin film 3a were measured by ESCA (manufactured by Shimadzu Corporation) to obtain atomic% of five elements of fluorine, carbon, oxygen, nitrogen and aluminum. These atomic percentages were converted to mass% using the atomic weight of each element. Of these, only the elements constituting the film, that is, fluorine mass% (F), carbon mass% (C), oxygen mass% (O), and nitrogen mass% (N) are used. The ratio of fluorine concentration (A (%)) was calculated.

A (%) = {F / (F + C + O + N)} X 100- ·-(1)

Here, as the outermost surface of the film, the surface of the precoated metal plate lb prepared as described above was measured as it was, that is, with an argon sputtering time of zero, and the inside of the film was measured by argon sputtering. The measurement was performed in the depth state in which the oil film 3b was etched in the thickness direction to 1Z2 of the film thickness. Here, the film thickness of 1Z2 is the argon sputtering time force, the depth state of the film in the time of 1Z2 until reaching the interface between the resin film 3b and aluminum, and the resin film 3b and aluminum Among the above-mentioned five elements (fluorine mass% (F), carbon mass% (C), oxygen mass% (O), nitrogen mass% (N) and aluminum mass% (A1)), This shows the depth state of the film during the argon sputtering time when the mass% of A1 corresponding to the metal plate is 50% of the total mass%. [0059] (urethane bond)

The resin film 3a was measured with FTIR (Thermo “Nikoreichi Japan”) to confirm the presence or absence of an absorption peak corresponding to the urethane bond.

[0060] (Adhesive peelability)

The adhesive peelability of the precoated metal sheets la of Examples 1 to 5 and Comparative Examples 1 to 7 was measured and evaluated. The results are shown in Table 1. The measurement and evaluation methods for adhesive peelability were as follows.

[0061] The adhesive peel strength was measured by a 180 degree peel test defined in JISK68542.

A coca inkjet paper photo label (manufactured by Co-Force Minolta Holdings Co., Ltd., product number QP10A4GMT) was used as the adhesive. In addition, as a measurement condition, a precoated metal plate la having a length of 100 mm × width of 60 mm and a label having a length of lOOmm × width of 6 mm were used, and the peeling speed was set to 50 mmZmin. The peel evaluation in Table 1 shows that “G” is used to indicate “Good” when the adhesive peel strength is 0.1 lNZ6 mm or less, and when 0.1 N / 6 mm is exceeded, “B” is used to indicate “bad”.

[0062] [Table 1]

From the results shown in Table 1, it was confirmed that the precoated metal sheets la of Examples 1 to 5 had a low adhesive peel strength. On the other hand, the precoated metal sheets la of Comparative Examples 1 to 4 and Comparative Example 7 resulted in high adhesive peel strength, while the precoated metal sheets la of Comparative Examples 5 and 6 had low adhesive peel strength, It is difficult to coat (adhere) the resin film 3a to the metal plate 2a. won.

[0064] In addition, the precoated metal plates la of Examples 1 to 5 were press-processed on the tray of the optical disk drive (the part on which the self-made CD is placed) and the upper cover of the optical disk drive (the part that covers the self-made CD). At that time, the surface of the disk produced without the occurrence of molding defects, etc., was also poor in appearance such as wrinkles, dirt and oil. Furthermore, as a result of measuring the friction coefficient of the precoated metal plates la of Examples 1 to 5 by a Bowden sliding test, it was confirmed that the friction coefficient was 0.04 to 0.05, and the lubricity was extremely good. It was. The friction coefficient was measured at a right angle to the rolling direction of the metal plate 2a with a 3/16 inch steel ball, a load of 0.5 kg, a sliding speed of 200 mmZmin, and no oil.

[0065] (Examples 6 to 13)

Next, examples relating to the weight-average molecular weight and appearance of the fluorocarbon resin as the main agent will be described. As Examples 6 to 13, precoated metal sheets la were produced according to the above production method. Each structure of the precoat metal plate la is as follows.

(Metal plate)

(Resin film)

Fluorine-based paint is applied to the outermost surface of the phosphate chromate film, baking is performed at a baking temperature (peak temperature of the metal plate 2a) of 250 ° C, and the film thickness is 5 μm. It was. Here, as the fluorine-based paint, a fluorine-based paint prepared by mixing the following two liquids was used.

(Main agent): Fluorine-based resin having a hydroxyl group. Eight kinds of weight average molecular weights in the range of 130,000-224,000 are used.

(Curing agent): Blocked isocyanate compound having three isocyanate groups.

[0066] Next, the glossiness of the surface of the precoated metal sheet la of Examples 6 to 13 was measured for the surface gloss, and the results are shown in Table 2. The measurement method was as follows. (Glossiness)

Using a gloss meter (manufactured by Nippon Denshoku Industries Co., Ltd.), the glossiness of the surface of the resin coating 3a of the precoated metal sheet la was measured under the 60 ° specular gloss condition based on JIS Z8741. The measurement was performed in the direction parallel to the rolling of the aluminum alloy sheet and in the direction perpendicular to the rolling, and the average value was calculated.

(Visual appearance evaluation)

10 people randomly selected to visually observe the appearance of the pre-coated metal sheet la, and when the number of people judged to be glossy was 9 or more, the number of people judged to be “glossy” or glossy A case of 8 or less was rated as “eraser”.

[0067] Next, the peelability of the pre-coated metal sheets la of Examples 6 to 13 was measured and evaluated.

The results are shown in Table 2. The measurement and evaluation method for the peelability of the adhesive was the same as in Example 1.

[0068] [Table 2]

From the results in Table 2, it was confirmed that the pre-coated metal sheets la of Example 613 all had a low adhesive peel strength!

In addition, the fluorine-based resin used as the main agent has a weight average molecular weight of 200,000 or less. Examples 6 to: LI pre-coated metal plates la were all 80 or more and exhibited excellent gloss even in visual evaluation.

Second embodiment

[0070] 1. Pre-coated metal sheet

Next, the configuration of the precoated metal sheet according to the second embodiment of the present invention will be described. The precoated metal plate lb according to the second embodiment of the present invention is formed on the surface of the metal plate 2b as a base material and the metal plate 2b as shown in FIG. The resin film 3b is controlled so that the ratio of is a predetermined value. Of these, the resin film 3b is composed of a fluorine-based resin matrix layer 4 and urethane beads 5 dispersed in the fluorine-based resin matrix layer 4, and the content and average particle size of the urethane beads 5 are as follows. The diameter is controlled to be a predetermined value. Here, the “urethane” in the urethane beads 5 means a polyurethane resin having undergone a crosslinking reaction with a urethane bond. The surface means at least one surface of the metal plate 2b. Next, each configuration will be described.

[0071] (1) Metal plate

The metal plate 2b used in the second embodiment is not limited to the most common cold-rolled steel plate, but also hot-dip galvanized steel plate, electrogalvanized steel plate, alloyed hot-dip galvanized steel plate and copper-plated steel plate. All types of steel plates such as plated steel plates, tin-plated steel plates, alloy steel plates such as stainless steel, aluminum or aluminum alloy plates, and non-ferrous metal plates such as copper or copper alloy plates are applicable. is there. Here, aluminum or aluminum alloy plates are preferred for applications that require lightness, such as a cover for an optical disk drive mounted on a notebook computer, a frame for a liquid crystal display device, and a cover for an in-vehicle electrical component. In particular, Al—Mg-based alloys conforming to JIS 5052 and JIS 5182 are more preferable.

[0072] (2) Grease film

(2-1) Ratio of fluorine concentration

The pre-coated metal sheet la used in the second embodiment of the present invention has a fluorine concentration ratio of 15% or more on the outermost surface of the resin film 3b as calculated by the formula (1), and is the same. The ratio of the fluorine concentration inside the film of the resin film 3b when calculated by the equation (1) is 15% or less. A (%) = {F / (F + C + 0 + N)} X 100 (1)

[0073] In this case, the ratio of the fluorine concentration is measured and converted by ESCA using fluorine mass%, carbon mass%, oxygen mass% and nitrogen mass% of the outermost surface of the resin coating 3b and inside the coating. And is calculated by equation (1). The outermost surface here refers to the surface on the side to which the adhesive (identification label L, etc. shown in Fig. 4) adheres, that is, the outermost surface of the pre-coated metal plate lb. It does not refer to the interface with 2b. The inside of the film refers to the part of the resin film 3b excluding the surface that adheres to the adhesive (the outermost surface) and the surface that adheres to the metal plate 2b. The inside of the film is the film of the resin film 3b. From the outermost surface, it indicates the approximately 1Z2 part of the film thickness in the thickness direction.

[0074] More specifically, the ratio of the fluorine concentration on the outermost surface of the film refers to the case where each elemental analysis is performed by ESCA after etching from the surface of the precoated metal plate lb toward the inside by argon sputtering or the like. It is a value obtained based on each element mass% of fluorine mass%, carbon mass%, oxygen mass% and nitrogen mass% obtained when the argon sputtering time is zero. In other words, zero argon sputtering time means that the surface is not etched at all by argon, so it can be defined as measurement at the outermost surface of the film. On the other hand, when argon sputtering is continued, the surface is deeply etched in proportion to the argon sputtering time, so that the longer the argon sputtering time, the deeper the internal element state is shown. After etching to some extent, the components of the metal plate 2b begin to appear. Therefore, the argon sputtering time when the mass% force of the elemental composition of the metal plate 2b exceeds 50% of the total mass% of the resin film 3b and the metal plate 2b It is defined as an interface. Assuming that the argon sputtering time to reach this interface is “T”, the ratio of the fluorine concentration inside the film according to the second embodiment is, in other words, the thickness from the outermost surface of the resin film 3b. The ratio of fluorine concentration in the 1Z2 part of the film thickness in the vertical direction is defined as the value obtained based on the element mass% obtained when the argon sputtering time is 1Z2 of the above “T”. .

[0075] According to the second embodiment, the fluororesin matrix layer 4 and the urethane beads 5 The resin film 3b is a non-uniform film when viewed microscopically. Therefore, when analyzing with ESCA, if the area of the analysis surface is too small, information on the region where the fluororesin matrix layer 4 is locally rich or the region where the urethane beads 5 are locally rich is conversely obtained. As a result, the ratio of fluorine concentration may vary at each measurement timing. Therefore, in the second embodiment, the measurement value when the area of the analysis surface is 3 mmφ is used so that average information of the resin film 3b can be obtained.

[0076] As shown in a comparative example to be described later, when the crosslinking reaction of the fluororesin matrix layer 4 is insufficient or when thermal degradation (decomposition) occurs, the ratio of the fluorine concentration on the outermost surface of the film May be less than 15%. In this case, since the ratio of fluorine on the outermost surface of the resin film 3b that affects the peelability of the adhesive film is small, the peel strength of the adhesive film on the resin film 3b increases, and dirt and oil are attached. It becomes easy. On the other hand, if the ratio of fluorine concentration inside the film exceeds 15%, the resin film 3b is firmly attached to the surface of the metal plate 2b unless a treatment such as forming a resin primer layer or an adhesive layer is performed. Can no longer be adhered to.

[0077] (2-2) Fluorine-based resin matrix layer

In the fluororesin matrix layer 4, it is desirable that the fluororesin as a main component and the curing agent react with each other by heat to have a crosslinked structure in the molecule. Further, the combination of the main agent and the curing agent includes a main agent that is a fluorocarbon resin having at least one of a hydroxyl group, a carboxyl group, and an amino group, and two or more isocyanate groups, preferably three or more isocyanate groups. It is preferable that the curing agent, which is an isocyanate compound having a chemical bond, is bonded (crosslinked) with at least one chemical bond among a urethane bond, an acid amide bond, and a urea bond. As a result, a stable crosslinked structure is formed in the fluorine-based resin matrix layer 4, and the fluorine-based resin matrix layer 4 (the resin film 3b) is more firmly bonded to the metal plate 2b. The above hydroxyl groups include alcohol-based hydroxyl groups and phenolic hydroxyl groups as well as derivatives that react with isocyanate groups in a broad sense. In addition, the above carboxyl group includes not only a carboxyl group but also all derivatives that react with isocyanate groups, such as a dehydrated carboxyl group. Similarly, the above amino groups include all derivatives that react with isocyanate groups. Cross-linked The degree of cross-linking of the fluorinated resin matrix layer 4 is preferably 80% or more in terms of the gel content specified in JIS K6796, which is an index of the degree of cross-linking.

[0078] (2-3) Urethane beads

In order to apply the pre-coated metal plate lb to the part that slides directly with the optical disk, etc., it is necessary to suppress wrinkling of the optical disk by sliding. Here, in order to prevent the optical disc or the like from being wrinkled, it is essential to soften the resin film 3b. In general, methods for softening the resin include a method for lowering the glass transition temperature of the resin and a method for suppressing the crosslinking reaction between the resin and the curing agent. In order to effectively soften the resin film 3b, it is most effective to soften the matrix resin, which is the main component of the resin film 3b, and in fact, these methods are used for the matrix resin. Thus, the resin film 3b can be softened.

[0079] However, if the softening of the resin film 3b is promoted by these methods, the tackiness of the resin film 3b will appear as a side effect, so that the adhesive to the resin film 3b (identification label L, figure (Refer to 4). On the other hand, when soft particles such as urethane beads 5 that do not soften the matrix resin of the resin film 3b are added to the resin film 3b (fluorinated resin matrix layer 4), the matrix resin It is possible to soften the entire resin film 3b without lowering the glass transition temperature or suppressing the crosslinking reaction. For this reason, it is possible to secure the anti-sticking property to the optical disk or the like without causing a tack that inhibits the anti-adhesion property of the adhesive (the identification label L, see FIG. 4) to the resin film 3b. Examples of such urethane beads 5 include Meltex (registered trademark) manufactured by Sanyo Chemical, Dimic beads (registered trademark) manufactured by Dainichi Seika, and Art Pearl (registered trademark) manufactured by Negami Kogyo.

[0080] (the content of polyurethane beads: 5 mass ^_0/0 to 50 mass ^_0/0 or less)

In order to improve the prevention of wrinkling on an optical disk or the like, it is preferable that the content ratio of the urethane beads 5 is larger than that of the fluorine-based resin matrix layer 4. When the content of the urethane beads 5 is less than 5 mass ^_0/0, the action of the amount of small tool cushion polyurethane beads 5 fixed to the fluorine-based榭脂matrix layer 4 is lowered, scratching preventive property is not It is enough. In addition, the higher the content of urethane beads 5, the more the viscosity of the paint in which urethane beads 5 are dispersed. Therefore, when the paint is applied to the metal plate 2b by roll coating or the like, the paintability with a uniform film thickness decreases. Furthermore, since the ratio of the fluorine-based resin matrix layer 4 to the resin film 3b decreases more than necessary, the ratio of fluorine concentration on the outermost surface of the film is less than 15%, and the adhesion prevention property of the adhesive (identification label L) is also improved. descend. For the above reasons, the content of the urethane beads 5 is 5% by mass or more and 50% by mass or less with respect to the fluororesin matrix layer 4. In order to ensure the high level of anti-sticking performance, the content of urethane beads 5 is preferably 10% by mass or more. To ensure stable paintability, the content of urethane beads 5 it is preferable is 40 mass ^_0/0 or less.

[0081] (Average particle diameter of urethane beads: 1.1 times to 5 times the average thickness of the fluorocarbon resin matrix layer)

In order to ensure that the urethane beads 5 are prevented from being scratched on an optical disk or the like, it is important that the average diameter of the urethane beads 5 is larger than the average thickness of the fluororesin matrix layer 4. As a result, as shown in FIG. 1, the cross-sectional shape of the resin film 3b becomes a fine uneven shape because the portion where the urethane beads 5 are present is convex. As a result, the contact area between the optical disk and the fluororesin matrix layer 4 is greatly reduced, and at the same time, softness and urethane beads 5 act as cushioning materials at the contact area, so Can be prevented.

Here, when the average particle size force of the urethane beads 5 exceeds 5 times the average thickness of the fluorinated resin matrix layer 4, most of the urethane beads 5 are fixed in the fluorinated resin matrix layer 4. Since it becomes difficult to determine, the effect which prevents the sliding wrinkle to an optical disk etc. falls. In addition, when the average particle size of the urethane beads 5 is 1.1 times or less than the average thickness of the fluorine-based resin matrix layer 4, the urethane beads 5 having such a small particle size have a fluorine-based resin matrix. The effect of preventing sliding wrinkles on an optical disk or the like is reduced because it is easily buried in the recording layer 4. Therefore, the average particle diameter of the urethane beads 5 is 1.1 times or more and 5 times or less of the average thickness of the fluorinated resin matrix layer 4, and the average thickness of the fluorinated resin matrix layer 4 is preferred. 1. More preferably 5 times or more and 4 times or less.

[0083] The average particle size of the urethane beads 5 and the average thickness force of the fluorine-based resin matrix layer 4 can be prevented from sliding on the optical disk or the like as long as the above relationship is maintained. However, on Even if the above relationship is maintained, if urethane beads 5 having a particle size larger than necessary are used, the average thickness of the fluororesin matrix layer 4 must be increased. Is thicker than necessary and is not economical. Conversely, when urethane beads 5 that are smaller than necessary are used, it is industrially difficult to control the relationship between the average particle diameter of the urethane beads 5 and the average thickness of the fluororesin matrix layer 4. Therefore, as urethane beads 5, it is desirable to use urethane beads having an average particle diameter of about 5 to 30 μm. The average thickness force of the fluororesin matrix layer 4 is 3 μm to 10 μm. Preferably it is. The average thickness of the fluorinated resin matrix layer 4 is a value obtained by measuring the weight of the resin film 3b per unit area and converting the specific gravity to 1.

[0084] There is a distribution in the particle size of actual urethane beads. For example, if the beads have an integrated volume of 50% and a particle size of about 8 μm, the particle size distribution ranges from a minimum of about 1 μm to a maximum of about 20 μm (Daiichi Seimitsu). See the particle size distribution of Daimic Beads (registered trademark) on the Japanese homepage of Sakai (synonymous with particle size distribution). Therefore, in the second embodiment, the average particle size is adopted as an index of the particle size of the urethane beads 5. The average particle diameter is a particle diameter of 50% cumulative volume measured with a laser diffraction type particle size distribution analyzer in a state where urethane beads 5 are dispersed in water.

Further, as described above, when the average particle diameter of the urethane beads 5 is larger than the average thickness of the fluorinated resin matrix layer 4, fine irregularities are formed on the surface of the resin film 3b. As a result, when the adhesive adheres to the resin film 3b, a fine air layer is formed on the fine irregularities, and the contact area between the adhesive and the resin film 3b decreases. Therefore, it is possible to keep the peel strength of the pressure-sensitive adhesive with respect to the resin film 3b low.

[0086] Next, the pre-coated metal plate lb according to the second embodiment includes a corrosion-resistant film (not shown) between the metal plate 2b and the fluororesin matrix layer 4 including the urethane beads 5. May be. The formation of the corrosion-resistant film imparts corrosion resistance to the precoated metal plate lb and improves the adhesion between the metal plate 2b and the resin film 3b. The structure of the corrosion resistant film is, for example, as follows.

[0087] (2-4) Corrosion resistant coating

The corrosion resistant coating is a conventionally known corrosion resistant coating containing Cr or Zr as a component. A phosphate chromate film, a chromate chromate film, a zirconium phosphate film, a zirconium oxide-based film, a coating type chromate film, a coating type zirconium film, or the like can be used as appropriate. Further, the adhesion amount of the corrosion-resistant film is preferably 10 to 50 mg / m ^{2 in} terms of Cr or Zr. If the adhesion amount of the corrosion resistant film is less than 10 mg / m ^2, the entire surface of the metal plate 2b cannot be uniformly coated, and it becomes difficult to ensure the corrosion resistance, so that it cannot withstand long-term use. On the other hand, if the adhesion amount exceeds 50 mgZm ² , the corrosion resistant film itself is cracked (peeled) in press molding and the like, and it becomes difficult to maintain the corrosion resistance over a long period of time.

[0088] 2. Method for producing precoated metal sheet

The method for producing the precoated metal plate lb of the present invention includes a first step of applying a fluorine-based paint in which urethane beads 5 are dispersed to the surface of the metal plate 2b, and the applied fluorine-based paint at 200 ° C or higher and 280 ° C. And a second step of forming a resin film 3b by baking treatment at C or lower. Hereinafter, each step will be described.

[0089] (1) First step

This is a process of applying a fluorine-based paint in which urethane beads 5 are dispersed on the surface of the metal plate 2b. The fluorine-based paint is a fluorine-based paint having at least one of a hydroxyl group, a carboxyl group and an amino group as a main agent. A mixture of a resin and an isocyanate compound having two or more, preferably three or more isocyanate groups, and more preferably a blocked isocyanate compound having blocked isocyanate groups as a curing agent. preferable. Further, a lubricant such as natural wax, petroleum wax, synthetic wax or a mixture thereof may be added to the fluorine-based paint. Furthermore, additives such as dyes and pigments for the purpose of coloring, various inorganic fillers for enhancing the scratch resistance of the resin film, and conductive additives are particularly within the scope of the present invention. It can be added without limitation.

[0090] The blocked isocyanate compound is a compound in which the active isocyanate group of the isocyanate compound is stabilized by a blocking agent such as an active hydrogen compound, and is not reactive at room temperature. In this blocked isocyanate compound, the blocking agent is dissociated by heating such as baking, and the active isocyanate group is regenerated to have reactivity. Blocking agents for blocked isocyanate groups include methanol, ethanol, and n-propanol. And alcohols such as tert-butanol, phenols such as phenol, m-taresol and isooctylphenol and resorcinol, ε-force prolatatam, oximes, acetylacetone, methyl ethyl ketone and ethylene chlorohydrin, etc. Active methylene compounds, sodium sulfite and the like. On the other hand, isocyanate compounds having blocked isocyanate groups include toluene diisocyanate, 4,4 'diphenylmethane diisocyanate (MDI), polymeric MDI, isophorone diisocyanate and Xamethylene diisocyanate and the like. In addition, polyisocyanates of polyhydric alcohol-modified types, polyisocyanates by burette bonds or isocyanate bonds, and the like are also included as isocyanate compounds.

[0091] In the fluorine-based paint using the blocked curing agent in this way, the isocyanate group of the curing agent is blocked at room temperature, so that the hydroxyl group, carboxyl group and amino group of the main agent and the isocyanate isocyanate of the curing agent are blocked. The reaction with the group (cross-linking reaction) does not proceed, and the fluorine paint is cured only by the baking process in the second step described later. Therefore, the fluorine-based paint can be stored for a long time in a state where the main agent and the curing agent are mixed, and the fluorine-based paint can be continuously applied to a long metal plate, which is industrially advantageous. It becomes.

[0092] The dispersion treatment method of the urethane beads 5 in the fluorine-based paint includes ultrasonic treatment, stirring treatment using a magnetic stirrer impeller, stirring treatment using a homogenizer, attritor, ball mill, bead mill, etc. Is included.

[0093] The fluorine-based paint can be applied by any method such as brush, roll coater, curtain flow coater, roller curtain coater, electrostatic coating machine, blade coater, die coater, etc. It is more preferable to use a roll coater that is uniform and easy to work. The coating amount is such that the metal plate 2b transport speed, the rotation direction and the rotation speed of the roll coater, etc., so that the fluororesin matrix matrix layer 4 with an average thickness of 3 to: LO m is formed on the surface of the metal plate 2b. Is set as appropriate.

[0094] Prior to application of the fluorine-based paint, a degreasing step of degreasing the surface of the metal plate 2b may be provided. For example, an aqueous alkali solution is sprayed on the surface of the metal plate 2b, and then washed with water to degrease the surface of the metal plate 2b. Further, as described above, the metal plate 2b and the fluorine-based resin film When a corrosion-resistant film is provided between the metal plate 2b and the surface of the metal plate 2b, a corrosion-resistant film can be formed following the degreasing step by spraying a chemical conversion treatment liquid containing chromium ions or the like onto the surface of the metal plate 2b.

[0095] (2) Second step

This is the process of forming the resin film 3b (fluorine-based resin matrix layer 4 containing urethane beads 5) on the surface of the metal plate 2b, and the fluorine-based paint applied in the first process is 200 ° C or higher and 280 ° C or lower Baking treatment with to cure (crosslink) the fluorine-based paint. When the fluorine-based paint is cured (crosslinked), the ratio of the fluorine concentration on the outermost surface of the film becomes 15% or more, and the resin film 3b whose ratio of fluorine concentration inside the film is 15% or less is formed. . In addition, the resin film 3b is firmly bonded to the metal plate 2b. Here, the baking temperature is the peak temperature of the metal plate 2b. At the same time, the urethane beads 5 are fixed to the fluororesin matrix layer 4.

[0096] When the baking temperature is less than 200 ° C, the fluorine coating is not sufficiently cured (cross-linked). When the baking temperature exceeds 280 ° C, the fluorine coating is thermally deteriorated (decomposed). The concentration ratio cannot be set to a desired value, and the peel strength of the adhesive on the surface of the film increases. The baking time is preferably 20-60 seconds. If the treatment time is less than 20 seconds, the baking will be insufficient. If the treatment time exceeds 60 seconds, the baking treatment time will be too long and the productivity per hour will tend to decrease. The baking process is performed using, for example, a hot air furnace, an induction heating furnace, a near infrared furnace, a far infrared furnace, or an energy beam curing furnace.

Next, an example according to the second embodiment will be described in detail.

In this example, in the precoated metal sheet lb according to the second embodiment, the content and average particle size of the urethane beads 5 dispersed in the resin film 3b (fluorine-based resin matrix layer 4) were changed. In this case, a test was conducted to confirm the change in the anti-sticking property to the optical disc and the change in the adhesive peelability.

[0098] (Examples 1 to 9)

As Examples 1 to 9, precoated metal plates lb were produced according to the above production method. Each configuration of the pre-coated metal plate lb is as follows.

(Metal plate) An aluminum alloy plate conforming to JIS5052-H34 was used with a thickness of 0.5 mm.

(Corrosion resistant coating)

(Resin film)

Fluorine paint with urethane beads 5 dispersed is applied to the outermost surface of the phosphate chromate film, baking is performed at 250 ° C (peak temperature of metal plate 2b), and resin film 3b (fluorine film) A fat matrix layer 4) was formed.

[0099] Here, as the fluorine-based paint, a fluorine-based paint prepared by mixing the following two liquids was used. In addition, a stirring process using a magnetic stirrer was used to disperse the urethane beads 5 in the fluorine paint. Furthermore, the average thickness (A) of the fluorine-based resin matrix layer 4, the average particle diameter (B), (B / A) and the content of the urethane beads 5 used are shown in Table 3. . (Main agent): Fluorine-based resin having a hydroxyl group. The weight average molecular weight is 182000.

(Curing agent): Blocked isocyanate compound having three isocyanate groups.

[0100] (Comparative Examples 1 to 9)

In correspondence with Comparative Examples 1 to 9, a precoated metal plate lb was produced so as to correspond to Examples 1 to 9. In Comparative Example 1, a pre-coated metal plate lb using a fluorine-based paint that does not contain urethane beads 5 is used. In Comparative Examples 2 to 7, urethane beads 5 are formed of an average particle diameter and a fluorine-based resin matrix layer 4. A pre-coated metal plate lb produced under the same conditions as in Examples 1 to 9 was used except that either the relationship with the average thickness or the content of urethane beads 5 did not satisfy the claims of the present invention. In Comparative Examples 8 and 9, the baking treatment was performed at the soaking temperature not satisfying the scope of the claims of the present invention.

[0101] Next, for the precoated metal plate lb of the resin coating 3b of Examples 1-9 and Comparative Examples 1-9, the ratio of the fluorine concentration in the outermost surface of the resin coating 3b and inside the coating was measured. The presence or absence of urethane bonds representing the cross-linked structure of the fluorinated resin matrix layer 4 was measured, and the results are shown in Table 3. In addition, the measuring method of each characteristic was as follows.

[0102] (Percentage of fluorine concentration)

Measure the outermost surface and the inside of the surface of the resin film 3b with ESCA (manufactured by Shimadzu Corporation). , 5% atomic% of fluorine, carbon, oxygen, nitrogen and aluminum were obtained. These atomic percentages were converted to mass% using the atomic weight of each element. Of these, only the elements constituting the film, that is, fluorine mass% (F), carbon mass% (C), oxygen mass% (O), and nitrogen mass% (N) are used. The ratio of fluorine concentration (A (%)) was calculated.

A (%) = {F / (F + C + O + N)} X 100- ·-(1)

Here, as the outermost surface of the film, the surface of the pre-coated metal plate lb prepared as described above was measured as it was, that is, with an argon sputtering time of zero, and the inside of the film was measured with argon. It was measured in a depth state in which the resin film 3b was etched in the thickness direction to 1Z2 of the film thickness by sputtering. Here, the film thickness of 1Z2 is the argon sputtering time force, the depth state of the film in the time of 1Z2 until reaching the interface between the resin film 3b and aluminum, and the resin film 3b and aluminum Among the above-mentioned five elements (fluorine mass% (F), carbon mass% (C), oxygen mass% (O), nitrogen mass% (N) and aluminum mass% (A1)), indicate the depth state of the film in the argon sputtering time mass% of A1, corresponding to the metal plate is 50% of the total mass ^_0/0 is as previously described.

[0104] Furthermore, in order to prevent the micro-uniformity of the resin film 3b from affecting the analysis, the area of the analysis surface was set to 3 mmφ. Both the outermost surface of the film and the inside of the film were contaminated with oils, etc., and the site was selected and measured.

[0105] (Urethane bond)

The resin film 3b was measured by FTIR (Thermo “Nikoreichi Japan Co., Ltd.”), and the presence or absence of an absorption peak corresponding to the urethane bond was confirmed.

[0106] Next, the anti-sticking property to the optical disk of the precoated metal plate lb of Examples 1 to 9 and Comparative Examples 1 to 9 and the peelability of the adhesive were measured and evaluated. The results are shown in Table 3. In addition, the measurement and evaluation methods of the anti-sticking property and the adhesive peelability were as follows.

[0107] (Anti-sticking property to optical disc)

Apply the entire recording surface of a commercially available optical disc to the surface of the precoated metal plate lb. After touching and rubbing 10 times left and right 10 times while lightly pressing with a finger, wrinkles on the surface of the optical disk were visually evaluated. At this time, in comparison with the optical disk samples shown in FIGS. 2 to 3, a sample with a near-fitting condition was selected, and the selected sample was used as a judgment result of the anti-fouling property of the precoated metal plate lb.

In the optical disc sample, (a) in Fig. 2 uses "E" to indicate "Excellent! /, (Excelent)", and (b) in Fig. 2 uses "G" to indicate "Good ( “(Good)”, “a” in FIG. 3 uses “NG” to indicate “Not So Good”, and (b) in FIG. It means “bad”. In addition, Table 3 shows the determination results of the anti-sticking property using “E”, “G”, “NG”, “B”!

However, wrinkles generated by rubbing the edges of the optical disc were excluded from the judgment targets, and strictly, only the sliding wrinkles between the surface of the resin film 3b and the disc recording surface were judged.

[0108] (Adhesive peelability)

The peel strength of the adhesive was measured by a 180 degree peel test specified in JIS K6854-2. As the adhesive, “Co-Force Inkjet Paper Photo Label” (manufactured by Co-Force Minolta Holdings Co., Ltd., product number QP10A4GMT) was used. In addition, as a measurement condition, a pre-coated metal plate having a length of 100 mm X a width of 60 mm and a label having a length of lOOmm X a width of 6 mm were used, and the peeling speed was set to 50 mmZmin. The peel evaluation in Table 3 indicates that “G” is used to indicate “Good” when the adhesive peel strength is 0.1 NZ6 mm or less, and when 0.1 N / 6 mm is exceeded, “B” is used to indicate “bad”.

[0109] [Table 3]

From the results in Table 3, the pre-coated metal plates lb of Example 19 all have an adhesive peel strength of less than 0.1 NZ6 mm, exhibit excellent adhesive peelability, and also have an anti-sticking property to the optical disc. It was good. In addition, as the content of urethane beads 5 increases, A tendency to improve the anti-tacking property was observed. When the content was 5% by mass or more, it was generally good, and when the content was 10% by mass or more, excellent anti-tacking property was shown. Furthermore, in Example 5, the content of urethane beads 5 is as high as 50% by mass, so the viscosity of the fluorine-based paint increased and the paintability was somewhat difficult, but this was not a problem in practical use. I got it.

[0111] On the other hand, the precoated metal plates lb of Comparative Examples 1 and 2 and Comparative Examples 4 to 7 both had an adhesive peel strength of less than 0.1 NZ6 mm and had excellent adhesive peelability. The anti-sticking property was inferior. Further, Comparative Examples 3, 8, and 9 were all excellent in the ability to prevent wrinkling on the optical disc. The adhesive peel strength exceeded 0.1N Z6 mm, and the adhesive peelability was inferior. Moreover, Comparative Example 3, since the content of the urethane beads 5 is beyond the scope of the claims of the present invention with 60 weight ^_0/0, increased significantly the viscosity of the fluoropolymer coating, there is difficulty in coatability It was.

[0112] In addition, the precoated metal plates lb of Examples 1 to 9 were pressed into portions corresponding to the optical disc drive tray (portion on which the optical disc was placed) and the optical disc on the upper cover of the optical disc drive. At that time, it was confirmed that there was no appearance defect such as wrinkles on the surface of the tray and the upper cover, which were free from molding defects, and adhesion of dirt and oil.

Claims

The scope of the claims

[1] A pre-coated metal plate comprising a metal plate and a resin film made of fluorine-based resin formed on the surface thereof,

When the ratio of the fluorine concentration on the outermost surface of the resin film is calculated by the formula (1), the ratio of the fluorine concentration is 20% or more,

A precoat characterized in that, when the ratio of fluorine concentration at the position of approximately 1Z2 of the film thickness inside the film of the resin film is calculated by the formula (1), the ratio of the fluorine concentration is 15% or less. Metal plate.

A (%) = {F / (F + C + 0 + N)} X 100 (1)

[2] The resin film is composed of a fluorine-based resin having at least one of a hydroxyl group, a carboxyl group and an amino group, an isocyanate compound having two or more isocyanate groups, a force S urethane bond, and an acid amide bond. 2. The precoated metal sheet according to claim 1, wherein the precoated metal plates are bonded with at least one kind of chemical bond among urea bonds.

[3] The precoated metal sheet according to [2], wherein the molecular weight of the fluorinated resin is 200,000 or less in terms of weight average molecular weight.

[4] The precoated metal sheet according to any one of claims 1 to 3, wherein a corrosion-resistant film is provided between the metal sheet and the resin film.

[5] The precoated metal plate according to any one of claims 1 to 3, wherein the metal plate is an aluminum plate or an aluminum alloy plate.

[6] A corrosion-resistant film is provided between the metal plate and the resin film,

The precoated metal plate according to any one of claims 1 to 3, wherein the metal plate is an aluminum plate or an aluminum alloy plate.

[7] The method for producing a precoated metal sheet according to claim 1, comprising a metal sheet and a resin film made of fluorine-based resin formed on the surface thereof. A first step of applying a fluorine-based paint to the surface of the metal plate;

And a second step of forming a fluorine-based resin film by baking the fluorine-based paint at 200 ° C. or more and 280 ° C. or less.

[8] A pre-coated metal plate comprising a metal plate and a resin film formed on the surface thereof, wherein the resin film is dispersed in the fluorine-based resin matrix layer and the fluorine-based resin matrix layer. With urethane beads,

The content of the urethane beads is 5% by mass or more and 50% by mass or less with respect to the fluorine-based resin matrix layer.

The average particle size force of the urethane beads is 1.1 times or more and 5 times or less of the average thickness of the fluorine-based resin matrix layer,

When the ratio of the fluorine concentration on the outermost surface of the resin film is calculated by the formula (1), the ratio of the fluorine concentration is 15% or more,

A (%) = {F / (F + C + 0 + N)} X 100 (1)

[9] The fluorine-based resin matrix layer of the resin film includes a fluorine-based resin having at least one of a hydroxyl group, a carboxyl group, and an amino group, and an isocyanate compound having two or more isocyanate groups. 9. The precoated metal sheet according to claim 8, wherein is bonded with at least one chemical bond among urethane bond, acid amide bond and urea bond.

[10] The average particle diameter force of the urethane beads is not less than 1.5 times and not more than 4 times the average thickness of the fluorinated resin matrix layer. Pre-coated metal plate.

[11] The content of the urethane beads is 10% by mass or more and 40% by mass or less with respect to the fluorine-based resin matrix layer. Pre-coated metal plate.

[12] The average particle size force of the urethane beads is 1.5 times or more and 4 times or less of the average thickness of the fluororesin matrix layer,

The precoated metal sheet according to claim 8 or 9, wherein a content of the urethane beads is 10% by mass or more and 40% by mass or less with respect to the fluorine-based resin matrix layer. .

[13] The precoated metal sheet according to [8] or [9], wherein a corrosion-resistant film is provided between the metal sheet and the resin film.

[14] Average particle size force of the urethane beads 1 of the average thickness of the fluororesin matrix layer

5 times or more and 4 times or less,

10. The precoated metal sheet according to claim 8, further comprising a corrosion-resistant film between the metal plate and the resin film.

[15] The urethane bead content is 10% by mass with respect to the fluororesin matrix layer.

% To 40% by mass,

16. The precoated metal sheet according to claim 12, further comprising a corrosion-resistant film between the metal plate and the resin film.

[17] The pre-coated metal plate according to claim 8 or 9, wherein the metal plate is an aluminum plate or an aluminum alloy plate.

[18] Average particle size force of the urethane beads 1 of the average thickness of the fluororesin matrix layer

5 times or more and 4 times or less,

10. The precoated metal plate according to claim 8, wherein the metal plate is an aluminum plate or an aluminum alloy plate.

[19] The urethane bead content is 10% by mass with respect to the fluororesin matrix layer.

% To 40% by mass,

[20] The precoated metal plate according to item 12, wherein the metal plate is an aluminum plate or an aluminum alloy plate.

[21] The precoated metal plate according to item 13, wherein the metal plate is an aluminum plate or an aluminum alloy plate.

[22] The precoated metal plate according to item 14, wherein the metal plate is an aluminum plate or an aluminum alloy plate.

[23] The precoated metal plate according to item 15, wherein the metal plate is an aluminum plate or an aluminum alloy plate.

[24] The precoated metal plate according to item 16, wherein the metal plate is an aluminum plate or an aluminum alloy plate.

[25] In the method for producing a precoated metal sheet according to claim 8, comprising a metal sheet and a resin film formed on the surface of the metal sheet.

Applying a fluorine-based paint in which urethane beads are dispersed to the surface of the metal plate; and

And a second step of forming the resin film by baking the fluorine-based paint at 200 ° C. or higher and 280 ° C. or lower.