JP2008161735A - Precoated metal sheet and manufacturing method of precoated metal sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a precoated metal sheet having flaw resistance improved compared to that of a conventional precoated metal sheet and a method of manufacturing the precoated metal sheet. <P>SOLUTION: The precoated metal sheet 1 is provided with a metal sheet 2 and a resin film 3. The resin film 3 comprises a matrix layer 4 formed by the cross-linking reaction of polyester resin having ≥0°C and ≤50°C glass transition temperature with a curing agent and soft beads 5 dispersed in the matrix 4 and having ≤10 MPa compressive strength in the 10% deformation of the single bead by a microcompression testing machine. The content of the soft beads 5 is ≥15 mass% and ≤50 mass% per the matrix layer 4, the average particle diameter of the soft beads is controlled to ≥1.1 and ≤5 times of the average thickness of the matrix layer 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a precoat metal plate and a method for producing a precoat metal plate used for outer plate materials and structural members such as household electric appliances and automotive in-vehicle parts, as well as building materials and roofing materials.

  Metal thin plate materials (metal plates) typified by steel plates, aluminum plates, and aluminum alloy plates have both high strength and formability, and by performing various moldings, household electrical products, automotive in-vehicle components, and more It is applied to various uses such as building materials. Metal plate molded products used for these applications may be subjected to surface treatment for the purpose of improving the appearance and corrosion resistance. Conventionally, this surface treatment has been mainly performed by a post-coating method after forming a metal plate into a predetermined shape, but recently, for the purpose of improving the workplace environment, simplifying the manufacturing process and reducing costs, etc. A pre-coating method in which a pre-coated metal plate that has been surface-treated in advance is formed into a predetermined shape is also fixed. Furthermore, in recent years, such pre-coated metal sheets have various functions such as fingerprint resistance, anti-sticking property, ground connection property, heat dissipation property, heat shielding property, antibacterial property, in order to meet the diversification and upgrading of products and equipment. Functional pre-coated metal plates with lubricity and the like have been developed and are widely used.

In such a pre-coated metal plate, since the surface treatment is performed, the film is not only required to have excellent formability, but the appearance after molding becomes the product appearance as it is, Excellent surface appearance and properties are required.
For example, in Patent Document 1, an aluminum alloy plate material, an epoxy resin, a urethane resin, and an acrylic resin alone or a mixture thereof is used as a base resin, SiO ₂ having a particle size of 0.1 μm or less is 5 to 40%, and a lubricant. There has been proposed a pre-coated metal plate which is coated with 5 to 60% of a coating having a thickness of 0.5 to 10 μm and has excellent formability and anti-sticking property with a friction coefficient controlled to 0.15 or less.

  Although the precoat metal plate described in Patent Document 1 is made of an aluminum alloy plate material, in general, a precoat metal plate made of aluminum is suitable for an application where lightness is required. Also used for covers and structural members of optical disc drive covers, liquid crystal display frames, back covers, automotive electronic components such as ECUs (Electronic Control Units), car stereos, car navigation systems, and optical disc auto changers Has been.

3A and 3B are perspective views showing a conventional optical disc drive and an optical disc used therefor, FIG. 3A shows a tray type optical disc drive, and FIG. 3B shows a slot-in type optical disc. Indicates drive.
As shown in FIG. 3A, the tray type optical disc drive 20 is a type in which an optical disc 10 such as a CD or a DVD is set in a tray 21 and the tray 21 is inserted into a cover 22. This method has been adopted in many products so far.
Further, as shown in FIG. 3B, recently, a slot-in type optical disk drive 30 has been developed in which a tray for setting the optical disk 10 does not come in and out, and only the optical disk 10 is inserted into the opening 31 and inserted. Yes. In such a slot-in type optical disk drive 30, the optical disk 10 goes in and out of the inner surface of the cover 32 of the optical disk drive 30. For this reason, when the optical disk 10 enters and exits, the surface of the optical disk 10 may rub against the inner surface of the cover 32 of the optical disk drive 30 and may cause sliding wrinkles. The prevention process is required on the inner surface side of the cover 32.
Conventionally, as the processing, coating (post coating) for preventing wrinkles has been applied to the inner surface of the cover 32 of the slot-in type optical disc drive 30 one by one.

Since it is very complicated to apply such post coating to each cover 32, even when the optical disk comes into contact, the surface of the optical disk is difficult to be scratched (hereinafter referred to as “anti-sticking property”). It was desired to develop a pre-coated metal plate provided with "."
In response to such a demand, the inventor of the present invention uses a fluororesin as a matrix layer, and urethane beads having a particle size such that the ratio between the film thickness and the particle size is within a predetermined range with respect to the matrix layer are predetermined. By forming a resin film blended at the blending ratio on the surface of the metal plate, it has excellent moldability and appearance that are fundamental for pre-coated metal plates to be molded and used, and is adhesive in applications where adhesives are used in combination. A pre-coated metal plate has been developed and is already put to practical use (see Japanese Patent Application No. 2005-294109). .

  Furthermore, the present inventor uses an epoxy-based resin as a matrix layer, and urethane beads having a particle size such that the ratio between the film thickness and the particle size is within a predetermined range are blended with the matrix layer at a predetermined blending ratio. By forming the resin film on the surface of the metal plate, it has the basic and excellent formability and appearance for the pre-coated metal plate to be molded and used. A pre-coated metal plate that can be attached and has a property of preventing wrinkling on an optical disk has been developed and proposed (see Japanese Patent Application No. 2006-85844).

  Patent Document 2 discloses a polyester resin, an epoxy resin, an acrylic resin, a nylon resin, a fluorine resin, and a urethane resin as a pre-coated metal plate assuming a slot-in optical drive. A pre-coated metal plate or the like that has a wrinkle-preventing property by containing any one of beads and a wax of carnauba, polyethylene, or microcrystalline is disclosed.

Japanese Patent No. 3338156 (paragraph numbers 0008 to 0017) JP 2006-97127 A

However, although the precoated metal plate described in Patent Document 1 can improve the moldability and scratch resistance of the precoated metal plate itself, there is no effect of improving the scratch resistance of the surface of the optical disk to be taken in and out. As described above, it is necessary to perform post-coating one by one on the inner surface of the cover 32 that has been molded. However, if such a process is performed, the process is very complicated, and thus the productivity is extremely high. However, there was a problem that it was low and extremely expensive.
Further, the anti-fouling property of the pre-coated metal plate described in Patent Document 2 cannot be said to have a sufficiently satisfactory anti-flaw property depending on the user. There was a strong demand for increased sticking prevention.

  The present invention has been made in view of the above problems, and prevents the optical disc from being wrinkled, that is, a pre-coated metal plate and a pre-coated metal plate with improved wrinkle-preventing property over conventional pre-coated metal plates. It is an object to provide a manufacturing method.

  As a result of diligent research to solve the above-mentioned problems, the present inventor strictly limited the particle size and addition amount of the soft beads that most dominate the anti-sticking property in order to enhance the anti-sticking property to the optical disk. , Improved basic anti-sticking property. In addition, by strictly limiting the type of resin and the glass transition temperature of the matrix layer in which the soft beads are dispersed, in the unlikely event that the soft beads are dispersed unevenly in the resin film, the matrix layer itself, not the soft beads, is the optical disc. Even when touched, a risk-sensitive resin film that can minimize wrinkles on the optical disc could be obtained. In addition, by using a coating that is a volatile component that increases the dispersibility of soft beads, the risk of the matrix (base material) layer being exposed due to non-uniform dispersibility of beads in the resin film is generated. It has been found that it is significantly reduced, and the present invention has been completed.

The pre-coated metal plate according to the present invention that has solved the above problems is a pre-coated metal plate having a resin film formed on the surface of the metal plate, and the resin film has a glass transition temperature of 0 ° C. or higher and 50 ° C. or lower. A matrix layer formed by a cross-linking reaction between a resin and a curing agent, and a soft bead dispersed in the matrix layer and having a compressive strength of 10 MPa or less when deformed by 10% of a single bead by a micro compression test, The content of the soft beads is 15% by mass or more and 50% by mass or less with respect to the matrix layer, and the average particle size of the soft beads is 1.1 times or more and 5 times or less of the average thickness of the matrix layer. Yes.
Here, it is preferable that the soft beads used in the precoated metal plate according to the present invention are urethane beads.

  As described above, the precoated metal sheet according to the present invention ensures excellent formability and appearance, which are fundamental to the precoated metal sheet to be molded and used, by the resin film comprising the matrix layer and the soft beads formed on the surface. be able to. And, by controlling the content and average particle size of soft beads such as urethane beads dispersed in the matrix layer, even if the optical disk contacts the precoated metal plate, the soft beads function as a cushioning material. In addition, it is possible to prevent the surface of the optical disk from becoming sticky.

As a result of ensuring excellent anti-fuzzing property to the optical disk and considering the balance with other characteristics, the average particle diameter of the soft beads is 1.1 times to 5 times the average thickness of the matrix layer. did. Moreover, the content rate of the soft bead was 15 mass% or more and 50 mass% or less with respect to the matrix layer.
That is, by setting the average particle diameter of the urethane beads to 1.1 times or more the average thickness of the matrix layer, the urethane beads can be prevented from being buried in the matrix layer, and the average particle diameter of the urethane beads can be reduced. By setting the average thickness of the matrix layer to 5 times or less, it is possible to prevent the urethane beads from falling off the matrix layer, so that the function of the urethane beads as a cushioning material can be brought out at a high level. Moreover, the function as a cushion material of urethane beads can be secured by setting the content of urethane beads to 15% by mass or more with respect to the matrix layer, and the content of urethane beads is set to 50% by mass or less. An increase in the viscosity of the paint is suppressed, and an appropriate paintability can be secured.

  In addition, since the matrix layer which is the main component of the resin film is a thermosetting polyester resin obtained by a cross-linking reaction between a polyester resin having a glass transition temperature of 0 ° C. or higher and 50 ° C. or lower and a curing agent, the matrix after the cross-linking reaction The layer is moderately softened. Therefore, even if a portion where the dispersion of soft beads is uneven is generated on the surface of the resin film after painting and the optical disc comes into contact with the portion, it is possible to reduce sticking of the optical disc by the exposed matrix layer. it can.

  In the precoated metal plate according to the present invention, the metal plate is preferably an aluminum plate or an aluminum alloy plate. In this way, not only is it difficult to bend even when the optical disc is in contact, but a lightweight product can be obtained when the product is manufactured by molding.

  Moreover, the manufacturing method of the precoat metal plate which concerns on this invention is a manufacturing method of the precoat metal plate which provides a resin film on the surface of a metal plate, Comprising: A coating process and a heating process are comprised.

  In the coating process, a polyester resin having a glass transition temperature of 0 ° C. or more and 50 ° C. or less, a curing agent, a soft bead having a compression strength of 10 MPa or less when deformed by 10% of a single bead by a micro compression test, and these are uniformly dispersed. In the heating step, the metal plate coated with the paint in the application step has a heating temperature of 200 ° C. to 300 ° C. and a heating time of 20 seconds. Heating is performed for 60 seconds or less. Here, the component ratio in the coating is adjusted in advance so that the content of the soft beads is 15% by mass or more and 50% by mass or less with respect to the matrix layer formed by the crosslinking reaction of the polyester resin and the curing agent. In addition, when the wet film thickness at the time of application becomes a dry film after the heating process, the average particle diameter of the soft beads is 1.1 times to 5 times the average thickness of the matrix layer. Apply to pre-calculated thickness. Thereby, the content of the soft beads is 15% by mass or more and 50% by mass or less with respect to the matrix layer formed by crosslinking reaction of the coating material and the polyester resin and the curing agent on the surface of the metal plate. A precoated metal plate provided with a resin film in which the average particle diameter of the soft beads is 1.1 to 5 times the average thickness of the matrix layer can be produced.

In the manufacturing method of the precoat metal plate of this invention, the content rate of the aromatic hydrocarbon type solvent in a volatile component is controlled to 30 mass% or more.
In this way, the soft beads dispersed in the paint are largely prevented from settling or reaggregating in the paint. Therefore, since the dispersion state of the soft beads in the paint is applied to the metal plate in a good state, the risk of generating a site where the dispersion of the soft beads is uneven in the resin film after coating can be greatly reduced. it can. As a result, the portion where the soft beads are partially reduced, that is, the portion where the matrix layer is exposed is greatly reduced. As a result, the probability that the surface of the optical disk will become wrinkled can be reduced.

  The soft beads used in the method for producing a precoated metal sheet according to the present invention are preferably urethane beads. In this way, since the soft beads function as a cushioning material, it is possible to reliably obtain a pre-coated metal plate that can prevent the surface of the optical disk from sticking.

  In the method for producing a precoated metal plate according to the present invention, the metal plate is preferably an aluminum plate or an aluminum alloy plate. In this way, not only is it difficult to bend even when the optical disc is in contact, but a lightweight product can be obtained when the product is manufactured by molding.

According to the precoated metal plate according to the present invention, excellent formability that is basic for a precoated metal plate that is formed and used by a resin film comprising a matrix layer and soft beads formed on the surface of the metal plate. In addition to ensuring the appearance, by optimizing the content and average particle size of the soft beads dispersed in the resin film (matrix layer), the surface of the resin film and the surface of the optical disk are in contact with each other. However, it is possible to make the anti-flaw preventing property to the optical disc higher than the conventional pre-coated metal plate.
According to the method for producing a pre-coated metal sheet according to the present invention, the pre-coated metal sheet that is formed and used by a resin film comprising a matrix layer and soft beads formed on the surface of the metal sheet is excellent and excellent. It is possible to produce a precoated metal plate that ensures formability and appearance. In particular, by appropriately regulating the ratio of the aromatic hydrocarbon solvent as the ratio of the volatile components, it is possible to produce a pre-coated metal plate that is further improved in preventing the optical disc from being wrinkled than a conventional pre-coated metal plate. .
In addition, according to the precoated metal plate of the present invention having such a resin film, the cost of paint for partial post-coating, the cost of environmental equipment such as painting equipment and exhaust, the labor cost of the coating operator, lot management And process management costs such as delivery management can be omitted, and the cost can be greatly reduced.

  Hereinafter, the best mode for carrying out the precoated metal sheet and the method for producing the precoated metal sheet according to the present invention will be described in detail with reference to the drawings as appropriate. In the drawings to be referred to, FIG. 1 is a partial cross-sectional view for explaining a configuration of a precoated metal plate according to the present invention. FIG. 2 is a flowchart for explaining the contents of the method for producing a precoated metal sheet according to the present invention. In each figure, the same constituent elements will be described with the same reference numerals.

1. Precoated Metal Plate As shown in FIG. 1, a precoated metal plate 1 of the present invention includes a resin film 3 formed on the surface of a metal plate 2 that is a base material. Among these, the resin film 3 includes a matrix layer 4 formed by a cross-linking reaction between a polyester resin and a curing agent, and soft beads 5 dispersed in the matrix layer 4. The average particle size is controlled to be a predetermined value.

Here, the surface of the metal plate 2 means at least one surface of the metal plate 2. For example, in the case where the contact surface of the optical disk 10 is limited to the inner surface of the cover 32 as in the cover 32 of the slot-in type optical disk drive 30 as shown in FIG. When the precoated metal plate 1 is used as the cover 32, the resin film 3 may be formed only on the surface that is the inner surface of the cover 32. In this case, the surface which is the outer surface of the cover 32 where the optical disk 10 does not directly contact is not particularly limited.
Although not shown, for example, when the optical disk 10 is in contact with both surfaces of the tray, such as a disk tray for an optical disk autochanger in which a plurality of optical disks 10 can be simultaneously mounted, the precoated metal plate 1 of the present invention is used. What is necessary is just to form the resin film 3 of this invention on both surfaces of the metal plate 2, when using as a tray. Next, each configuration will be described.

(Metal plate)
The metal plate 2 used in the present invention is not particularly limited. In addition to the most common cold-rolled steel plate, hot-dip galvanized steel plate, electrogalvanized steel plate, alloyed hot-dip galvanized steel plate, copper-plated steel plate, tin-plated steel plate, etc. All of the above-mentioned various 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. Here, an aluminum plate or an aluminum alloy plate is preferable for applications that require lightness, such as covers for optical disk drives mounted on notebook computers, frames for liquid crystal display devices, and covers for in-vehicle electrical components. Since these applications require not only lightness but also strength, in particular, an Al—Mg-based alloy represented by 5052 and 5182 specified in JIS is more preferable.

(Resin film)
As described above, the resin film 3 includes the matrix layer 4 and the soft beads 5 dispersed in the matrix layer 4, and is formed on the surface of the metal plate 2.

(Matrix layer)
The polyester resin used for the matrix layer 4 is a polyester resin having a glass transition temperature of 0 ° C. or higher and 50 ° C. or lower, more preferably 5 ° C. or higher and 40 ° C. or lower. By setting the glass transition temperature within this range, the matrix layer 4 after the cross-linking reaction is moderately softened, so that the soft beads 5 are not uniformly dispersed in the resin film 3 formed on the surface of the precoated metal plate 1. Even when the portion is generated, the exposed matrix layer 4 is relatively soft, so that the optical disc 10 can be prevented from wrinkling. In addition, when the pre-coated metal plate 1 is manufactured as a coil, it is possible to prevent a blocking phenomenon in which the surfaces that the resin coatings 3 that face each other come into contact with each other due to the coil temperature at the time of winding are less likely to occur. .

Here, 50 ° C., which is defined as the upper limit value of the glass transition temperature, is in operation of an electronic device using an optical disk such as an optical disk drive device, an audio device, an optical disk autochanger, or a car navigation drive device in which the optical disk 10 is used. The internal environmental temperature is taken into consideration.
That is, when a polyester resin having a glass transition temperature exceeding 50 ° C. is used for the matrix layer 4, the matrix layer 4 exists as a hard glass even at 50 ° C. where these devices are actually operating. Therefore, when there is a portion where the soft beads 5 are dispersed non-uniformly, the optical disc 10 may come into contact with the hard glassy matrix layer 4, which may cause the optical disc 10 to become sticky.
When a polyester resin having a glass transition temperature lower than 0 ° C. is used for the matrix layer 4, the matrix layer 4 becomes too soft and the tackiness (adhesiveness) of the resin film 3 becomes large. When the baked metal plate 2 is wound up as a coil, there is a possibility that a blocking phenomenon occurs in which the surfaces with which the resin film 3 contacts are thermally fused.
As such a polyester resin having a glass transition temperature of 0 ° C. or more and 50 ° C. or less, those made by Dainippon Ink Chemical Co., Ltd. and Nippon Paint Co. can be suitably used. In addition, the same paints made by Kansai Paint Co., Dainippon Paint Co., Ltd., Kawakami Paint Co., etc. can be used.

  The matrix layer 4 preferably uses an amine-based curing agent, particularly a melamine-based curing agent as a curing agent. Melamine-based curing agents are not only easy to paint by dissolving in organic solvents, but the paint life is long at room temperature, but when heated, the crosslinking reaction proceeds easily in a short time, and soft beads The dispersibility of No. 5 is also good, and furthermore, it has excellent paintability, so that it becomes easy to apply the paint to the surface of the metal plate 2.

  In addition, since the cross-linking reaction between the polyester resin and the curing agent by heat forms a three-dimensional network structure by connecting hands, the strength of the resin film 3 is ensured, and the resin film 3 and the metal plate are secured. 2 has the function of further strengthening the adhesive strength with 2. Furthermore, since the resin film 3 in which a polyester resin having a glass transition temperature of 0 ° C. or more and 50 ° C. or less and a curing agent as described above undergoes a crosslinking reaction retains an appropriate softness even after the crosslinking reaction, the pre-coated metal should be used. Even if the resin film 3 formed on the surface of the plate 1 has a portion where the dispersion of the soft beads 5 is not uniform and the matrix layer 4 is in direct contact with the optical disc 10, the optical disc 10 is less likely to be wrinkled. Anti-sticking property is maintained.

(Soft beads)
In order to prevent the optical disk 10 from wrinkling when the optical disk 10 enters and exits the slot-in type optical disk drive 30, it is indispensable to soften the resin film 3 as described above. As will be described in detail later, in the present application, the resin film 3 is partially softened using soft beads 5 typified by urethane beads, but conventional means for softening the resin film is essentially a resin film. Softening the entire resin film rather than partially softening, that is, without relying on additives such as beads, a method of lowering the glass transition temperature of the resin used for the matrix layer itself, And a method for suppressing the crosslinking reaction between the resin and the curing agent.
Although these methods have the effect of softening the resin film as a whole rather than partially, it can be said that the effect of softening the resin film is great, but as a side effect, tackiness appears on the entire surface of the resin film. Further, since no beads are used, the surface becomes smooth. When the surface of such a smooth and tacky resin film comes into contact with the surface of the optical disk 10, the optical disk 10 is attached to the resin film, and the movement of the optical disk 10 itself when the optical disk 10 is inserted and removed or the optical disk There arises a problem that the operation of the device using the optical disk 10 such as the drive 30 is impaired.

  On the other hand, in the present invention, the matrix layer 4 of the resin film 3 is not softened, but is added by adding soft fine particles, that is, soft beads 5 to the resin film 3 (matrix layer 4). In addition, a technique for softening the dendritic membrane 3 is employed. According to such a method, as described above, the matrix layer 4 does not necessarily need to be softened, so that the tackiness of the matrix layer 4 such as lowering the glass transition temperature or suppressing the crosslinking reaction is increased. There is no need to do.

The softness of the soft bead 5 in the present invention refers to a soft bead having a compressive strength of about 10 MPa or less when deformed by 10% using a single bead in a micro-compression test (when deformed by 10% of a single bead).
As a testing machine for performing a micro compression test, for example, there is a micro compression test machine MCT-W500 manufactured by Shimadzu Corporation. By using this test machine, a compression test is performed on a single bead having a particle diameter of about 1 μm to 100 μm. It can be performed. More specifically, a single bead having a particle size of 5 to 10 μm, preferably about 8 μm, is set on the lower pressure plate of the testing machine, and simultaneously applying a load while compressing the single bead while lowering the upper pressure indenter. And the load when the bead diameter decreases by 10% is taken as the 10% compression load value. If this 10% compressive load value is P (N) and the measured bead particle size is d (mm), the compressive strength St (MPa) at the time of 10% deformation can be calculated by the following equation (1) ( (See Japan Mining Association Journal, 81.10.24 (1965)). The smaller the compressive strength St (MPa) at the time of 10% deformation, the softer the beads. In the present invention, the compressive strength St (MPa) at the time of 10% deformation is required to be 10 MPa or less, and more desirably 5 MPa or less.
St = 2.8P / (Πd ² ) (1)
(However, in Equation (1), Π represents the circumference ratio.)

  According to the method using such soft beads 5, since the matrix layer 4 does not cause tackiness, the problem of sticking between the resin film 3 and the optical disk 10 does not occur, and the optical disk 10 is prevented from being wrinkled. Can be improved. As such soft beads 5, for example, urethane beads, ethylene / methyl methacrylate copolymer (EMMA) beads, low density polyethylene (LDPE) beads and the like can be suitably used. As urethane beads, SANYO Kasei's Meltex (registered trademark), Dainichi Seika's Dymic beads (registered trademark), Negami Kogyo Art Pearl (registered trademark), etc. are preferably used. Can do. In addition, as for EMMA beads, soft beads A, soft beads B, etc. manufactured by Sumitomo Seika Co., Ltd. can be preferably used, and as flow beads (registered trademark) manufactured by Sumitomo Seika Co., Ltd., as LDPE beads, Can do.

  In the above description, it has been described that the use of the soft beads 5 can ensure the anti-fouling property to the optical disk 10 without softening the matrix layer 4. The beads 5 and a polyester resin having a glass transition temperature of 0 ° C. or higher and 50 ° C. or lower are used. Thus, by using together with the soft matrix layer 4, the whole resin film 3 can be softened as a result. For this reason, compared with what has softened only the part of the soft bead 5, the wrinkle prevention property can be improved further. Since the entire resin film 3 is softened, there is a concern about the problem of tackiness as described above. However, since the soft beads 5 are provided, the operation due to the tackiness is performed even when the optical disk 10 is taken in and out. There is no hindrance.

  That is, not only using the soft matrix layer 4 alone, but also using the soft beads 5 to control the average thickness of the matrix layer 4 and the particle size of the soft beads 5, the surface of the resin film 3 is The surface state is not smooth but uneven. That is, most part of the resin film 3 that comes into contact with the surface of the optical disk 10 becomes the tip of the soft bead 5, and the opportunity of direct contact between the optical disk 10 and the matrix layer 4 with tackiness can be greatly suppressed. As a result, it is possible to avoid the problem of tackiness that the optical disk 10 and the resin film 3 stick. Since the soft beads 5 have a particle size distribution as will be described later, although not shown, even if the thermosetting polyester resin may be thinly coated up to the tip of the relatively small soft beads 5, Anti-sticking property can be ensured by the soft beads 5 larger than that which can be adjacent.

  Further, in the present invention, even when the dispersion of the soft beads 5 becomes non-uniform on the surface of the precoated metal plate 1 after the resin film 3 is formed and an exposed portion of the matrix layer 4 is formed, the soft beads 5 are combined. Since the matrix layer 4 is also softened moderately, it is possible to prevent wrinkles on the surface of the optical disc 10 even when the optical disc 10 and the precoated metal plate 1 are in direct contact.

(Content of soft beads: 15% by mass or more and 50% by mass or less)
In order to enhance the prevention of wrinkling on the optical disk 10, it is preferable that the content of the soft beads 5 is larger than that of the matrix layer 4. If the content rate of the soft beads 5 is less than 15% by mass, the amount of the soft beads 5 fixed in the matrix layer 4 is small, the function as a cushioning material is lowered, and the anti-sticking property is inferior. Moreover, since the viscosity of the coating material in which the soft beads 5 are dispersed increases as the content of the soft beads 5 is increased, the film thickness is increased when the coating material is applied to the metal plate 2 by roll coating or the like. It becomes difficult to uniformly control (that is, paintability deteriorates). For the above reasons, the content of the soft beads 5 is 15% by mass or more and 50% by mass or less with respect to the matrix layer 4. In order to ensure more stable paintability, the content of the soft beads 5 is preferably 40% by mass or less.

(Average particle size of soft beads: 1.1 to 5 times the average thickness of the matrix layer)
In order to improve the prevention of wrinkling of the optical beads 10 with the soft beads 5, it is important that the average particle diameter of the soft beads 5 is larger than the average thickness of the matrix layer 4. By making the average particle diameter of the soft beads 5 larger than the average thickness of the matrix layer 4, as shown in FIG. 1, the cross-sectional shape of the resin film 3 has a fine uneven shape in which the portions where the soft beads 5 are present are convex. It becomes the resin film 3 to have. Therefore, not only the soft soft beads 5 function as a cushion material when the optical disc 10 and the resin film 3 are in contact with each other, but also the direct contact between the optical disc 10 and the matrix layer 4 can be greatly reduced. The anti-sticking property can be further enhanced without causing malfunction of the optical disk 10.

  Here, when the average particle diameter of the soft beads 5 exceeds 5 times the average thickness of the matrix layer 4, soft beads 5 that are not fixed in the matrix layer 4 and fall off are generated. The effect of increasing the prevention of wrinkling on the optical disk 10 is reduced. If the average particle diameter of the soft beads 5 is less than 1.1 times the average thickness of the matrix layer 4, the soft beads 5 having a small particle diameter are easily embedded in the matrix layer 4. The effect of increasing the anti-sticking property to the skin is reduced. Therefore, the average particle diameter of the soft beads 5 is 1.1 to 5 times the average thickness of the matrix layer 4. The average thickness of the matrix layer 4 is more preferably 1.5 times or more and 4 times or less.

  In addition, if the average particle diameter of the soft beads 5 and the average thickness of the matrix layer 4 are maintained in such a relationship, it is possible to improve the anti-sticking property to the optical disc 10, but the above relationship However, if the soft beads 5 having a larger particle size than necessary are used, the average thickness of the matrix layer 4 must be increased, so that the resin film 3 becomes thicker than necessary, which is not economical. . On the other hand, when soft beads 5 smaller than necessary are used, it becomes industrially difficult to control the relationship between the average particle diameter of the soft beads 5 and the average thickness of the matrix layer 4. Therefore, the average particle diameter of the soft beads 5 is preferably about 5 to 30 μm, and the average thickness of the matrix layer 4 is more preferably 3 μm or more and 15 μm or less. The average thickness of the matrix layer 4 in the present invention can be determined by measuring the weight of the resin film 3 per unit area and converting the specific gravity to 1.

  Here, as described above, there is a distribution in the particle size of the soft beads 5. For example, it is known that the particle size distribution of beads having an integrated volume of 50% particle size of about 8 μm is distributed from a minimum of about 1 μm to a maximum of about 20 μm (for example, Dainichi Seika Kogyo Co., Ltd.). Particle size distribution (synonymous with particle size distribution) of Dymic Beads (registered trademark) on the website of Therefore, in the present invention, the average particle diameter is adopted as an index of the particle diameter of the soft beads 5. In addition, the average particle diameter in this invention means an integrated volume 50% particle diameter measured with the laser diffraction type particle size distribution measuring instrument etc. in the state which disperse | distributed the soft bead 5 in water.

In addition, the precoat metal plate 1 of this invention may be provided with a corrosion resistant film (not shown) between the metal plate 2 and the resin film 3 including the soft beads 5 and the matrix layer 4.
By forming the corrosion-resistant film, corrosion resistance is imparted to the pre-coated metal plate 1 and adhesion between the metal plate 2 and the resin film 3 is improved.

As a structure of such a corrosion-resistant film, a conventionally known corrosion-resistant film containing Cr or Zr as a component can be used. For example, a phosphate chromate film, a zirconium phosphate film, a zirconium oxide-based film, a coating-type zirconium film, or the like can be used as appropriate. Moreover, as for the adhesion amount of a corrosion-resistant film | membrane, 10-50 mg / m < ² > is preferable in Cr or Zr conversion value. When the adhesion amount of the corrosion-resistant film is less than 10 mg / m ^2, the entire surface of the metal plate 2 cannot be uniformly coated, and it becomes difficult to ensure the corrosion resistance, so that it cannot withstand long-term use. Moreover, when the adhesion amount of a corrosion-resistant film | membrane exceeds 50 mg / m < ² >, in shaping | molding etc., a crack (peeling) will arise in corrosion-resistant film | membrane itself, and it will become difficult to maintain high corrosion resistance over a long period of time.

2. Next, with reference to FIG. 2, the manufacturing method of the precoat metal plate which concerns on this invention is demonstrated in detail.
As shown in FIG. 2, the manufacturing method of the precoat metal plate concerning this invention comprises application | coating process S1 and heating process S2. Hereinafter, each step will be described. In addition, the operation | work which adjusts the coating material which has the predetermined composition mentioned later is also contained in application | coating process S1 of this invention.

(Coating process)
The coating step S1 includes, as essential components of the coating, a polyester resin having a glass transition temperature of 0 ° C. or higher and 50 ° C. or lower, a curing agent, and a soft bead having a compressive strength of 10 MPa or less when deformed by 10% of single beads by a micro compression test 5 and a volatile component for uniformly dispersing them, and applying a thermosetting polyester paint (hereinafter simply referred to as “paint”) to the surface of the metal plate 2. .
In addition, among the above-described essential components, the content of the soft beads is 15% by mass or more and 50% by mass or less with respect to the matrix layer 4 formed by cross-linking reaction of the polyester resin and the curing agent through the heating step S2 described later. Adjust the ratio in advance so that

Here, as the above-described polyester resin, a saturated polyester resin obtained by condensation polymerization of a polyhydric alcohol and a polybasic acid is used.
Among these, examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol, propylene glycol, neopentyl glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, glycerin, trimethylolethane, A trihydric alcohol such as methylolpropane, or a tetrahydric or higher alcohol can be used.

Examples of the polybasic acid include dibasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, and sebacic acid, tribasic acids such as trimellitic anhydride, and tetrabasic or more polybasic acids. An acid or the like can be used.
These polyhydric alcohols and polybasic acids may be used in one kind or two or more kinds at the same time for condensation polymerization, but the glass transition temperature of the polyester resin produced by condensation polymerization is measured, and 0 to 50 ° C. Only the thing below degrees C can be used for the manufacturing method of the precoat metal plate 1 of this invention.
The glass transition temperature can be measured by a conventional method such as differential scanning calorimetry (DSC).

  As the curing agent, an amine curing agent having two or more amino groups or an isocyanate curing agent having two or more isocyanate groups can be used. However, an amine curing agent is used because of the stability of the paint. It is desirable to use a melamine-based curing agent.

The volatile component is necessary to dissolve or disperse the curing agent and the soft beads 5 in the above-described polyester resin, and to secure an optimum paint viscosity for coating.
The soft beads 5 can be uniformly dispersed in the paint by sufficiently stirring with a stirrer, but if the stirring is stopped and left for a long time, it will settle or aggregate due to gravity or the like. There is.
The volatile component is heated in the heating step S2 to be described later and volatilized when the crosslinking reaction is performed, and does not remain as a component of the resin film 3. However, depending on what the component is, the paint As a result, the dispersibility of the soft beads 5 in the inside is affected, and as a result, the distribution of the soft beads 5 in the resin film 3 after the coating and crosslinking reaction is greatly affected.

  In the present invention, the content ratio of the aromatic hydrocarbon solvent in the volatile component is preferably 30% by mass or more. When the content ratio of the aromatic hydrocarbon solvent in the volatile component is 30% by mass or more, the effect of suppressing sedimentation and reaggregation of the soft beads 5 dispersed in the paint can be suitably obtained. Therefore, since the uniformity of the paint is stably maintained, the possibility that a portion where the dispersion of the soft beads 5 is non-uniformly generated in the resin film 3 after coating can be greatly reduced. Thereby, it is possible to more reliably prevent the surface of the optical disc 10 from becoming sticky. Here, it is more preferable that the content ratio of the aromatic hydrocarbon solvent is 50% by mass or more in view of improving the anti-fouling property to the surface of the optical disk 10. The content ratio of the aromatic hydrocarbon solvent in the volatile component may be less than 5% by mass, but it is difficult to effectively obtain the above-described effects.

  Specific examples of volatile components include water, isophorone, cyclohexanone, methyl isobutyl ketone, methanol, butanol, diacetone alcohol, butyl cellosolve, ethylene glycol monobutyl ether, ethyl acetate, butyl acetate, etc. It is desirable that an aromatic hydrocarbon solvent such as xylene, toluene, trimethylbenzene, naphthalene, aromatic naphtha, or the like be used alone or mixed to obtain a content ratio of 30% by mass or more.

  And it adjusts so that a content rate may be 15 mass% or more and 50 mass% or less, and disperse | distributes the soft bead 5 uniformly in a coating material. Examples of the treatment method for dispersing the soft beads 5 in the paint include ultrasonic treatment, stirring treatment using a magnet stirrer or impeller stirrer, and stirring treatment using a homogenizer, attritor, ball mill, bead mill, and the like.

The coating may be applied by any means such as a brush, roll coater, curtain flow coater, roller curtain coater, electrostatic coating machine, blade coater, die coater, etc. In particular, the coating amount becomes uniform. It is preferable to use a roll coater that is easy to work.
The average particle size of the soft beads 5 is 1.1 times to 5 times the average thickness of the matrix layer 4 by adjusting the coating amount according to the particle size of the soft beads 5 used. It can be. In the present invention, the average particle size of the soft beads 5 is preferably about 5 to 30 μm, so that the coating amount is the matrix layer 4 having an average thickness of 3 to 15 μm on the surface of the metal plate 2. The conveyance speed of the metal plate 2, the rotation direction and rotation speed of the roll, the pressing pressure between the rolls (nip pressure), and the like may be adjusted as appropriate. By adjusting these, the thickness (that is, wet film thickness) of the paint before drying transferred to the metal plate 2 can be changed. As a result, it is possible to adjust the average thickness of the matrix layer 4 of the dried film after the crosslinking reaction by the heating step S2 described later, and as described above, the average particle diameter of the soft beads 5 is the matrix layer 4 The average thickness can be 1.1 times or more and 5 times or less.

Prior to the application of the paint, a degreasing step (not shown) for degreasing the surface of the metal plate 2 may be provided. In the degreasing step, for example, the surface of the metal plate 2 can be degreased by spraying an acid or alkaline aqueous solution on the surface of the metal plate 2 and then washing with water.
Further, as described above, when a corrosion-resistant film is provided between the metal plate 2 and the resin film 3, the chemical conversion treatment liquid containing chromium ions or the like is sprayed on the surface of the metal plate 2 following the degreasing step. A corrosion-resistant film can be formed by washing with water or applying a treatment liquid containing chromium ions and drying.

(Heating process)
The heating step S2 is a step of heating the metal plate 2 having the coating material applied in the applying step S1 under the conditions that the heating temperature is 200 ° C. or higher and 300 ° C. or lower and the heating time is 20 seconds or longer and 60 seconds or shorter. In this heating step S2, volatile components contained in the paint are evaporated and dried, and the heated paint undergoes a crosslinking reaction to form a resin film 3 (matrix layer 4 including soft beads 5) on the surface of the metal plate 2. And is firmly bonded to the metal plate 2. Needless to say, the soft beads 5 heated in the heating step S <b> 2 are fixed in a properly dispersed state in the matrix layer 4.

The heating temperature does not affect the scratch resistance of the optical disc 10 by the resin film 3, but if the heating temperature is less than 200 ° C, the crosslinking reaction of the paint becomes insufficient, and the heating temperature is 300 ° C. When the temperature exceeds the range, the paint (resin film 3) is thermally deteriorated (decomposed), and therefore, the temperature is preferably 200 ° C. or higher and 300 ° C. or lower. The heating time is preferably 20 to 60 seconds. If the heating time is less than 20 seconds, the heating tends to be insufficient, and if it exceeds 60 seconds, the heating time is too long, so the productivity per hour decreases, which is not preferable.
This heating step S2 can be 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, the pre-coated metal plate and the method for producing the pre-coated metal plate of the present invention will be specifically described by comparing an example that satisfies the requirements of the present invention with a comparative example that does not satisfy the requirements of the present invention.

  The items examined were the type of resin used in the paint, the glass transition temperature, the average thickness of the matrix layer of the resin film, the content of the soft beads dispersed in the matrix layer, the average particle size, and the aroma in the volatile components of the paint. It is a content ratio of the group hydrocarbon solvent. Then, the prevention of wrinkling on the optical disc, paintability, and blocking properties were evaluated. This will be described in detail below.

[Examples 1 to 10]
As shown in Table 1, Examples 1 to 10 have a glass resin having a glass transition temperature of 0 ° C. or higher and 50 ° C. or lower, a curing agent, and soft beads having a compressive strength at the time of 10% deformation defined in the present invention. The resin film was provided by applying a paint containing a volatile component to disperse these to a metal plate, and then baking the metal plate coated with the paint by heating at a heating temperature of 250 ° C. for a heating time of 30 seconds. A precoated metal plate was produced. Here, urethane beads were used as the soft beads. In addition, the metal plate used for Examples 1-10 used what formed the phosphoric acid chromate process in advance on both surfaces as a corrosion-resistant film for improving corrosion resistance. The adhesion amount of the phosphoric acid chromate film was 20 mg / m ² in terms of Cr. Each structure of a precoat metal plate is as follows.

(Metal plate)
The metal plate used was an aluminum alloy plate having a thickness of 0.5 mm and a JIS standard 5052-H34.

(Resin film)
The resin film is formed by applying a paint containing a polyester resin having a glass transition temperature of 0 ° C. or more and 50 ° C. or less, in which urethane beads are dispersed as soft beads on a phosphate chromate film, and the heating temperature and the heating time described above are applied. It formed by performing heat processing.
Here, the heating method of the metal plate is a continuous baking method in which the metal plate coated with the paint rides on the conveyor and moves from the entrance to the outlet of the oven, and the time for the metal plate to pass through the oven is defined as the heating time, This was 30 seconds. Moreover, the highest temperature reached of the metal plate confirmed by the heat label attached to the metal plate was defined as the heating temperature, and this was set to 250 ° C.

(Polyester resin having a glass transition temperature of 0 ° C to 50 ° C)
As the polyester resin having a glass transition temperature of 0 ° C. or higher and 50 ° C. or lower, those made by Dainippon Ink Chemical Co., Ltd. and Nippon Paint Co., Ltd. were used.

[Comparative Examples 1 to 12]
As a control for Examples 1 to 10, precoated metal sheets of Comparative Examples 1 to 12 were produced. Manufacture of the precoat metal plate of Comparative Examples 1-12 followed the conditions and structure which manufactured Examples 1-10 except the point described below.
In Comparative Example 1 and Comparative Example 2, the glass transition temperature does not satisfy the numerical range defined in the present invention. In Comparative Examples 3 to 6, a type of resin that is not a polyester resin specified in the present invention was used. In Comparative Example 7 and Comparative Example 8, the relationship between the average particle diameter of the soft beads and the average thickness of the matrix layer does not satisfy the numerical range defined in the present invention. Moreover, the comparative example 9 and the comparative example 10 do not satisfy | fill the numerical range prescribed | regulated by this invention in the addition amount of a soft bead. Further, Comparative Example 11 and Comparative Example 12 are comparative examples using beads not having compressive strength at the time of 10% deformation defined by the present invention (that is, beads that are not soft).

  The average thickness of the matrix layer of the resin film was determined for each of the precoated metal plates of Examples 1 to 10 and Comparative Examples 1 to 12 thus manufactured. The average thickness of the matrix layer can be obtained by measuring the weight of the resin film per unit area and converting the specific gravity to 1.

  About the manufactured precoat metal plate which concerns on Examples 1-10 and Comparative Examples 1-12, the wrinkle prevention property to an optical disk, coating property, and blocking property were evaluated. Evaluation of wrinkle-preventing property, paintability and blocking property to the optical disk was performed as follows.

(1) Prevention of wrinkle on optical disc The prevention of wrinkle on optical disc is made by bringing the recording surface of a commercially available optical disc into contact with the resin film surface of the pre-coated metal plate and rubbing it 10 times back and forth while gently pressing it with a finger. After that, wrinkles on the surface of the optical disk were visually observed. The case where no wrinkles were observed was indicated as “◯”, and the case where any wrinkles existed was indicated as “x”. The test was conducted by heating to 50 ° C.
This is tested 100 times for one type of example or comparative example, and when the probability of “◯” is 95% or more, the anti-sticking property is considered good (pass), and the probability of “○” Is less than 95%, the anti-sticking property is regarded as poor (failed).

(2) Paintability The paintability was confirmed by measuring the viscosity of the paint. Specifically, the Ford Cup # 4, which is widely used for viscosity measurement of paint, is used, and the viscosity is measured in a state where the solid content of the paint is 30% or more, that is, the volatile component ratio does not exceed 70%. If the viscosity is 120 seconds or less, the paint can be applied. If the viscosity is more than 120 seconds and within 180 seconds, the paintability is somewhat difficult (indicated as “paintability is somewhat difficult” in Table 1). Was judged as poor paintability (shown as “paintability poor” in Table 1).

(3) Blocking property The blocking property is 1 minute by lightly sandwiching a hot press heated to 70 ° C. with the coating (resin coating) surfaces of the pre-coated metal plate facing each other through the coating step and the heating step. It was judged that it was good if the coating film surfaces of the pre-coated metal sheet held and taken out were not adhered to each other, and defective when they were adhered (shown as “blocking failure” in Table 1).

  Table 1 shows the conditions and configuration for producing the pre-coated metal plates according to Examples 1 to 10 and Comparative Examples 1 to 12, and evaluations for preventing wrinkling on optical disks, paintability and blocking properties. In addition, the underline in Table 1 indicates that the requirements defined in the present invention are not satisfied.

  As shown in Table 1, all of the precoated metal plates of Examples 1 to 10 were able to obtain excellent evaluation results with respect to the anti-sticking property to the optical disk. Moreover, the precoat metal plate of Examples 1-10 was a thing without any problem practically about coating property and blocking property.

  On the other hand, since the pre-coated metal plates of Comparative Examples 1 to 12 do not satisfy any of the requirements defined in the present invention, the evaluation results of any one of the anti-sticking property to the optical disc, the paintability and the blocking property Became unpreferable.

  Specifically, the precoated metal plate of Comparative Example 1 was good in terms of preventing wrinkling on the optical disk, but the glass transition temperature of the polyester resin did not satisfy the numerical range defined in the present invention. The blocking property was poor. Therefore, it was suggested that it is a pre-coated metal plate that cannot be put into practical use when manufactured by continuous treatment with a coil material.

Since the precoated metal plate of Comparative Example 2 had a glass transition temperature of the polyester resin that exceeded the numerical range specified in the present invention, the anti-fouling property to the optical disc was poor.
Moreover, since the precoat metal plate of Comparative Examples 3-6 used resin which is not a polyester resin, the wrinkle prevention property to an optical disk became inferior.

  In the pre-coated metal plates of Comparative Examples 7 and 8, since the relationship between the average particle diameter of the soft beads and the average thickness of the matrix layer did not satisfy the requirements defined in the present invention, both of them prevented the optical disk from being wrinkled. Became defective.

Since the precoated metal plate of Comparative Example 9 did not satisfy the numerical range defined by the present invention in terms of the content of soft beads, the ability to prevent wrinkling on the optical disk was poor.
And since the precoated metal plate of Comparative Example 10 had a soft bead content exceeding the numerical range defined in the present invention, the anti-sticking property to the optical disk was good, but the viscosity of the paint was Significantly increased, paintability was poor.

  The pre-coated metal plates of Comparative Examples 11 and 12 were beads whose compressive strength at the time of 10% deformation of the beads used did not satisfy the numerical range defined in the present invention, that is, beads that were not soft. The wrinkle-preventing property was poor.

  As described above, the precoat metal plate and the method for producing the precoat metal plate according to the present invention have been described in detail with reference to the best embodiments and examples, but the content of the present invention is not limited to these descriptions. It should be construed broadly based on the claims. Further, the contents of the present invention can be variously changed and modified within a range that does not impair the effects of the present invention.

For example, in order to further improve the ability to prevent wrinkling on an optical disk, a predetermined amount of one or two lubricants such as palm oil, carnauba wax, polyethylene wax, and microcrystalline wax may be contained in the paint.
Also, commonly used pigments, pigment dispersants, fluidity modifiers, leveling agents, anti-waxing agents, preservatives, stabilizers, etc. are used to ensure the paint performance and general performance as a pre-coated metal plate. May be included.
Furthermore, you may provide the undercoat layer for improving both adhesiveness between a resin film, a metal plate, and / or a corrosion-resistant film. Thereby, the moldability of a precoat metal plate can be improved more.

It is sectional drawing which shows typically the structure of the precoat metal plate which concerns on this invention. It is a flowchart explaining the content of the manufacturing method of the precoat metal plate which concerns on this invention. (A) And (b) is a perspective view which shows the conventional optical disk drive and the optical disk used for this, (a) shows a tray type optical disk drive, (b) shows a slot-in type optical disk drive. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Precoat metal plate 2 Metal plate 3 Resin film 4 Matrix layer 5 Soft bead S1 Application | coating process S2 Heating process 10 Optical disk 20 Tray type optical disk drive 21 Tray 22 Cover 30 Slot-in type optical disk drive 31 Opening part 32 Cover

Claims (7)

A pre-coated metal plate provided with a resin film formed on the surface of the metal plate,
The resin film has a matrix layer formed by a crosslinking reaction between a polyester resin having a glass transition temperature of 0 ° C. or more and 50 ° C. or less and a curing agent,
A soft bead dispersed in the matrix layer and having a compressive strength of 10 MPa or less when deformed by 10% of a single bead by a micro compression test,
The content of the soft beads is 15% by mass or more and 50% by mass or less with respect to the matrix layer,
The average particle size of the soft beads is 1.1 to 5 times the average thickness of the matrix layer.   The precoated metal sheet according to claim 1, wherein the soft beads are urethane beads.   The pre-coated metal plate according to claim 1 or 2, wherein the metal plate is an aluminum plate or an aluminum alloy plate. A method for producing a pre-coated metal plate provided with a resin film on the surface of the metal plate,
As essential components of the coating material, a polyester resin having a glass transition temperature of 0 ° C. or more and 50 ° C. or less, a curing agent, a soft bead having a compressive strength of 10 MPa or less when deformed by 10% of a single bead by a micro-compression test, and these are uniform Among them, the content of the soft beads is 15% by mass or more and 50% by mass or less based on the matrix layer formed by the crosslinking reaction of the polyester resin and the curing agent. When the ratio of the coating is adjusted in advance so that it becomes a dry film after the heating step, the average particle diameter of the soft beads becomes 1.1 to 5 times the average thickness of the matrix layer. So that the wet film thickness calculated in advance so as to apply to the metal plate,
The metal plate on which the paint is applied in the application step is heated under conditions of a heating temperature of 200 ° C. or more and 300 ° C. or less and a heating time of 20 seconds or more and 60 seconds or less, and the polyester resin and the surface are applied to the surface of the metal plate. A heating step of forming a cross-linking reaction with a curing agent to form the resin film;
The manufacturing method of the precoat metal plate characterized by including.   The pre-coated metal sheet according to claim 4, wherein the volatile component includes an aromatic hydrocarbon solvent, and a content ratio of the aromatic hydrocarbon solvent in the volatile component is 30% by mass or more. Manufacturing method.   The method for producing a precoated metal sheet according to claim 4 or 5, wherein the soft beads are urethane beads.   The said metal plate is an aluminum plate or an aluminum alloy plate, The manufacturing method of the precoat metal plate of any one of Claims 4-6 characterized by the above-mentioned.

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