WO2007116670A1

WO2007116670A1 - Precoated metal plate

Info

Publication number: WO2007116670A1
Application number: PCT/JP2007/056159
Authority: WO
Inventors: Nobuo Hattori
Original assignee: Kabushiki Kaisha Kobe Seiko Sho
Priority date: 2006-03-27
Filing date: 2007-03-26
Publication date: 2007-10-18
Also published as: KR101009869B1; KR20080106303A; WO2007116670A9; CN101384427A; CN101384427B

Abstract

This invention provides a precoated metal plate that can prevent the occurrence of defects in an optical disk, and, at the same time, can maintain high peel strength of an adherend to a resin film, and can realize easy adhesion of the adherend to the surface of the resin film. The precoated metal plate comprises a metal plate and a resin film provided on the surface of the metal plate. The resin film comprises an epoxy resin matrix layer and soft beads dispersed in the epoxy resin matrix layer. For the soft beads, the compressive strength at single bead 10% deformation by a microcompression test is not more than 10 MPa. The content of the soft beads is not less than 5% by mass and not more than 50% by mass based on the epoxy resin matrix layer, and the average particle diameter of the soft beads is not less than 1.1 times and not more than 5 times the average thickness of the epoxy resin matrix layer.

Description

Specification

Pre-coated metal plate

Technical field

TECHNICAL FIELD [0001] The present invention relates to an outer plate material such as a household electric product or an in-vehicle component for automobiles, and further to a pre-coated metal plate used for a building material, a roof material or the like.

Background art

[0002] Metal thin plate materials (metal plates) represented by steel plates, aluminum plates, and aluminum alloy plates have both high strength and workability. It is applied to various uses such as parts and building materials. The metal plate processed products used in these applications may be subjected to surface treatment for the purpose of improving the appearance and corrosion resistance. This surface treatment has traditionally been a post-coat method, in which a metal plate is processed into a predetermined shape.Recently, the workplace environment has been improved, the processing process has been simplified, and costs have been reduced. For the purpose of the above, a pre-coat method in which a pre-coated metal plate that has been surface-treated on a metal plate is molded into a predetermined shape has been established. Furthermore, in recent years, such pre-coated metal sheets have various functions such as fingerprint resistance, anti-scratched property, ground connection, heat dissipation, etc. in order to meet the diversification and upgrading of products and equipment. Functional pre-coated metal plates that have been imparted with properties, heat shielding properties, antibacterial properties, lubricity, etc. 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 Patent Document 1, an aluminum alloy sheet is made of epoxy resin, urethane resin and acrylic resin alone or a mixture thereof, and SiO having a particle size of 0.1 μm or less is 5-40%.

2

, And paint containing 5 to 60% of lubricant, 0.5 ~: Pre-coated metal plate with excellent formability and anti-sticking property with a friction coefficient of 0.15 or less was proposed. ing.

[0004] The pre-coated metal sheet described in Patent Document 1 is composed of an aluminum alloy sheet material cover. In general, pre-coated metal plates made of aluminum have gained popularity in applications where lightness is required. Examples include optical disk drive covers for laptop computers, LCD display frames, and knock covers. It is also used for covers and structural members such as ECUs (Electron! C Control Units), car stereos, car navigation systems, and optical disc auto changers that are on-vehicle electrical components. Of these, optical discs such as CDs and DVDs are installed when used in optical disc drives and optical disc autochangers. Recently, with the widespread use of writable optical disc drives, music CDs etc. are personally edited. In addition, there are many cases of producing self-made optical discs. Such self-made optical discs may be used in a state where an adhesive such as an identification label for identification is attached to the surface of the optical disc.

[0005] However, the use of such identification labels has created new challenges. For example, part of the identification label was peeled off due to the heat of the device, etc., and it became necessary to prepare for the danger that the exposed adhesive part would reattach to each part in the device.

As shown in FIG. 4, there is a conventional optical disc drive 20 in which the optical disc 10 is set on a tray 21 and the tray 21 is inserted into a cover 22. Although not shown, recently, a slot-in type optical disk drive has been developed in which only the optical disk is inserted into the opening of the optical disk drive and inserted without entering and exiting the tray on which the optical disk is set. In such a slot-in type optical disk drive, the optical disk goes in and out of the inner surface of the cover of the optical disk drive. Therefore, there is a problem that the surface of the optical disk rubs against the inner surface of the cover of the optical disk drive when the optical disk enters and exits, and sliding wrinkles easily enter. To prevent this, wrinkles enter the surface of the optical disk. Preventive measures are required.

[0007] Therefore, in the pre-coated metal plate, the adhesive is difficult to adhere in an application in which an adhesive is used together, and it is difficult for dirt and oil to stick to it. It is required to combine the characteristics with difficulty in brazing. In response to such a problem, the present inventors have used a fluorocarbon resin as a matrix layer, urethane beads as a predetermined compounding ratio, and a particle size such that the ratio to the film thickness is within a predetermined range. A pre-coated metal plate that is molded and used by forming a resin film blended on the surface of the metal plate In addition to having excellent basic moldability and appearance, it is difficult to adhere dirt and oil to sticky materials in applications where sticky materials are used together. Developed a pre-coated metal plate that is difficult to scratch the surface and has characteristics

(Japanese Patent Application 2005-294109).

Patent Document 2 discloses a pre-coated aluminum alloy plate having a film having a base resin layer strength including resin beads. However, since the resin beads disclosed in Patent Document 2 are a relatively hard material such as acrylic or fluorine resin, the precoated aluminum alloy plate itself is prevented from being damaged, but the optical disk or the like is in contact with it. In this case, there is a problem that the surface of the optical disk or the like is damaged.

Patent Document 1: Japanese Patent No. 3338156 (paragraph numbers 0008 to 0017)

Patent Document 2: JP 2004-98624 A

Disclosure of the invention

Problems to be solved by the invention

However, on the other hand, depending on the user, even if there is a risk that an adhesive such as an identification label sticks to the surface of the precoated metal sheet, the resin film of the precoated metal sheet may be covered with a double-sided adhesive tape. There is a desire to affix parts such as scratch resistance to the surface.

[0009] Therefore, the present invention has been made in view of the problem of force, can prevent wrinkles from entering the optical disc, and can maintain a high peel strength of the adhesive to the resin film. The present invention provides a pre-coated metal sheet that has the property that an adhesive easily adheres to the surface of the film.

Means for solving the problem

[0010] In order to solve the above problems, a precoated metal plate according to the present invention is a precoated metal plate comprising a metal plate and a resin film formed on the surface thereof, wherein the resin film is an epoxy resin. A resin bead matrix layer and a soft bead dispersed in the epoxy-based resin matrix layer and having a compressive strength of 10% or less at the time of deformation of 10% or less by a micro-compression test are contained in the soft bead. The rate is 5% by mass or more and 50% by mass or less with respect to the epoxy resin matrix layer, and the average particle size force of the soft beads is 1.1 times or more the average thickness of the epoxy resin matrix layer. Which is configured to be less than 5 times is there.

[0011] According to such a configuration, even if an optical disk or the like comes into contact with each other, the content and average particle diameter of the soft beads dispersed in the epoxy-based resin matrix layer (resin film) are controlled. Since soft beads work as a cushioning material, wrinkles are unlikely to enter the surface of an optical disk or the like due to the resin film. In addition, since the matrix layer, which is the main component of the film, is made of epoxy resin, the peel strength of the adhesive to the resin film can be maintained high, so the adhesive strength when attaching parts to the film surface with adhesive tape, etc. It becomes good.

[0012] In the pre-coated metal plate, the soft beads may be configured as a pre-coated metal plate which is urethane beads.

[0013] Among the soft beads, urethane beads are particularly difficult, and thus using urethane beads increases the effect of the beads functioning as a cushioning material, and makes the surface of the optical disk more sticky. This can be further prevented.

[0014] In the precoated metal sheet, the epoxy resin matrix layer is obtained by crosslinking a main agent composed of bisphenol A type epoxy resin and a curing agent composed of a urea compound or a phenol compound by heat. It can be configured as a film.

[0015] Epoxy resin having such a combination is not only easy to be made into a paint by dissolving in an organic solvent, but has a long paint life at room temperature. Since the curing reaction proceeds, the dispersibility of the soft beads and other additives is good, and the coating property is excellent, so that it is easy to apply the coating on the surface of the metal plate. Moreover, the curing reaction by heat forms a three-dimensional network structure necessary for securing the strength as a film, and further strengthens the adhesive force between the resin film and the metal plate.

[0016] As an additive for imparting lubricity to the pre-coated metal plate, the epoxy-based resin matrix layer may be configured to contain a fluorine-based lubricant. According to such a configuration, by selecting a relatively soft and fluorine-based lubricant as the lubricant, it is possible to improve the lubricity without reducing the anti-sticking property to the optical disk. As a result, the movement of the optical disc itself and the operation of the optical disc drive when the optical disc is inserted and removed are smoothly performed.

[0017] In the pre-coated metal plate, the pre-coated metal plate is made of tetrafluoride-tylene. It can be configured as a coated metal plate.

According to such a configuration, the use of tetrafluorinated titanium having a high fluorine content can maximize the improvement of lubricity.

[0018] In the pre-coated metal sheet, the amount of the fluorine-based lubricant added represents the ratio of the fluorine concentration on the outermost surface of the resin film, according to the following formula (1):

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

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

It can be configured that the fluorine concentration ratio is within the range of 10% or less.

[0019] According to such a configuration, by controlling the ratio of the fluorine component in the film to a certain value or less, the peel strength of the adhesive to the resin film can be maintained high. It is possible to avoid a decrease in the adhesive strength when attaching the parts.

[0020] It is preferable that the soft beads have an average particle diameter of 1.5 to 4 times the average thickness of the epoxy resin matrix layer.

According to such a configuration, the action of the soft beads as a cushioning material is improved, and wrinkles can be further prevented from entering the surface of the optical disk or the like by the rosin film.

[0021] The pre-coated metal plate may be configured such that the content of the soft beads is 10% by mass or more and 40% by mass or less with respect to the epoxy resin matrix layer. .

According to such a configuration, the effect of soft beads as a cushioning material is improved, and wrinkles enter the surface of an optical disk or the like more by the sebum film. In addition, when an epoxy paint in which soft beads are dispersed on the metal plate surface is applied to form a resin film, the viscosity of the epoxy paint is adjusted to a predetermined range, thereby improving the paintability.

[0022] The pre-coated metal plate may be configured to include a corrosion-resistant film between the metal plate and the resin film.

According to such a configuration, the corrosion resistance of the pre-coated metal plate is improved, and the resin film is more firmly bonded to the metal plate when and when. [0023] The pre-coated metal plate can be configured such that the metal plate is an aluminum plate or an aluminum alloy plate.

According to such a configuration, lighter weight can be achieved compared to the case where other metal plates are used.

The invention's effect

[0024] According to the precoated metal sheet of the present invention, only the excellent formability and appearance that are fundamental to a precoated metal sheet that is molded and used by the resin film formed on the surface of the metal sheet. By optimizing the content and average particle size of the soft beads dispersed in the Nagu resin film (epoxy resin matrix layer), even if the resin film surface and the optical disk surface slide, It can be prevented from entering. In addition, the peel strength of the adhesive to the resin film can be maintained at a high level, and adhesion when a part is attached to the film surface with double-sided adhesive tape, etc. makes it easy for the adhesive to stick to the surface of the resin film. It is possible to provide a pre-coated metal plate having both of the above. Brief Description of Drawings

FIG. 1 is a cross-sectional view schematically showing a configuration of a precoated metal sheet according to the present invention.

[Fig. 2] Photomicrographs of an optical disk swatch for determining the anti-sticking property to the optical disk. (A) is a swatch sample with excellent anti-sticking property, and (b) is a swatch with good anti-sticking property. This is a sample.

[Fig. 3] Photomicrographs of an optical disc sample for judging the anti-sticking property to the optical disk. (A) is a sample with slightly poor anti-sticking property, and (b) is a poor anti-sticking property. This is a sample.

FIG. 4 is a perspective view schematically showing a configuration of an optical disc drive.

Explanation of symbols

[0026] 1 Pre-coated metal plate

2 Metal plate

3 Grease film

4 Epoxy resin matrix layer

5 Soft beads 10 Optical disc

20 Optical disk drive

21 tray

22 Cover

BEST MODE FOR CARRYING OUT THE INVENTION

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

1. Pre-coated metal plate

As shown in FIG. 1, the precoated metal plate 1 of the present invention includes a metal plate 2 that is a base material and a resin film 3 formed on the surface of the metal plate 2. Of these, the resin film 3 is composed of the epoxy resin matrix layer 4 and the soft beads 5 dispersed in the epoxy resin matrix layer 4, and the content and average particle size of the soft beads 5 are as follows. Is controlled to be a predetermined value. Here, the surface means at least one surface of the metal plate 2. Next, each configuration will be described.

[0028] (1) Metal plate

In addition to the most common cold-rolled steel sheet, there are no particular restrictions on the metal plate 2 used in the present invention, hot-dip galvanized steel sheet, electrogalvanized steel sheet, galvannealed steel sheet, copper-plated steel sheet, tin Various steel plates such as 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. is there. Here, aluminum or aluminum alloy plates are preferred 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. In particular, Al—Mg alloys represented by JIS stipulated by 5052 and 5182 are more preferable.

[0029] (2) Grease film

The resin film 3 includes an epoxy resin matrix layer 4 and soft beads 5 dispersed in the epoxy resin matrix layer 4, and is formed on the surface of the metal plate 2.

[0030] (2-1) Epoxy resin matrix layer

The epoxy resin matrix layer 4 is obtained by cross-linking a main agent composed of bisphenol A type epoxy resin and a curing agent capable of urea compound or phenol compound by heat. It is preferable that Epoxy resin in such a combination is not only easy to paint by dissolving in an organic solvent, but has a long paint life at room temperature, but easily cures in a short time when heat is applied. The reaction progresses, the dispersibility of the soft beads and lubricant is good, and the coating property is also excellent, so that it is easy to apply a coating on the surface of the metal plate 2. Moreover, the curing reaction by heat forms a three-dimensional network structure necessary to ensure the strength of the film, and it is easy to further strengthen the adhesive force between the resin film 3 and the metal plate 2. is there. Furthermore, it is more preferable to use a urea-based compound as the curing agent because it can suppress discoloration due to heat during the curing reaction.

The epoxy resin matrix layer 4 may contain a predetermined amount of a fluorine-based lubricant typified by tetrafluoroethylene.

[0031] (2-2) Soft beads

In order to apply the pre-coated metal plate 1 to a portion that slides directly with the optical disk or the like when the optical disk or the like enters or exits, it is necessary to prevent wrinkles from entering the optical disk or the like due to sliding. Here, in order to prevent wrinkles from entering the optical disk or the like, it is indispensable to soften the resin film 3. Usually, methods for softening the resin film 3 include a method of lowering the glass transition temperature of the resin and a method of suppressing a crosslinking reaction between the resin and the curing agent. In order to effectively apply the resin film 3, it is most effective to soften the matrix resin, which is the main component of the resin film 3, and these methods are actually applied to the matrix resin. It is possible to soften the resin film 3 by using.

[0032] However, if the softening of the resin film 3 is promoted by these methods, the tackiness of the resin film 3 appears as a side effect, so the lubricity of the resin film 3 is significantly reduced. There is a problem that the movement of the optical disk itself and the operation of the optical disk drive are impaired when the optical disk is inserted and removed. On the other hand, if soft fine particles, that is, soft beads 5 are added to the resin coating 3 (epoxy resin matrix layer 4), the softening of the matrix resin of the resin coating 3 is not sufficient. The entire resin film 3 can be softened without lowering the glass transition temperature or suppressing the cross-linking reaction. For this reason, it is possible to ensure the ability to prevent wrinkling on an optical disk or the like without impairing the lubricity of the resin film 3.

[0033] The soft bead 5 in the present invention is a single bead by a micro compression test. This means that the compression strength when deformed by 10% (when deformed by 10% single bead) is about lOMPa or less.

For example, the MCT-W500 manufactured by Shimadzu Corporation can be used as a testing machine for micro compression testing. By using this testing machine, a single particle size of 1 μm force or about 100 μm can be obtained. A compression test can be performed on one bead. More specifically, a single bead having a particle size of 5 to: L0 m, preferably about 8 m, is set on the lower pressure plate of the tester, and the single bead is subjected to compression deformation while lowering the upper pressure indenter. At the same time, the load is measured, 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 10% deformation can be calculated by the following equation (2) ( (See Japan Mining Association, 81. 10. 24 (1965)). The smaller the compressive strength St (MPa) at 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 lOMPa or less, and more desirably 5 MPa or less.

St = 2.8PZ (nd ² ) · · · · Equation (2)

(However, in Equation (2), Π represents the circumference.)

[0034] 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, Meltex (registered trademark) manufactured by Sanyo Kasei Co., Ltd., Dymic beads (registered trademark) manufactured by Dainichi Seiyaku, Art Pearl (registered trademark) manufactured by Negami Kogyo Co., Ltd., etc. are preferably used. be able to. As EMMA beads, Soft Beads A and B made by Sumitomo Seika Chemicals Co., Ltd. can be suitably used. LDPE beads are flow beads manufactured by Sumitomo Seika Co., Ltd. (Registered trademark) or the like can be preferably used.

[0035] (Content of soft beads: 5% by mass or more and 50% by mass or less)

In order to improve the prevention of wrinkling on an optical disk or the like, it is preferable that the content of the soft beads 5 is greater than that of the epoxy resin matrix layer 4. If the content of the soft beads 5 is less than 5% by mass, the effect as a cushioning material is reduced when the amount of the soft beads 5 fixed in the epoxy resin matrix layer 4 is small, and the anti-sticking property is inferior. Soft beads 5 When the content ratio of the metal plate 2 is increased, the viscosity of the paint in which the soft beads 5 are dispersed increases. Paintability at film thickness decreases. For the above reasons, the content of the soft beads 5 is set to 5% by mass or more and 50% by mass or less with respect to the epoxy resin matrix layer 4. In addition, in order to secure the anti-sticking performance at a high level, the content of the soft beads 5 is preferably 10% by mass or more. The content is preferably 40% by mass or less!

[0036] (Average particle diameter of soft beads: 1.1 times to 5 times the average thickness of epoxy resin matrix layer)

In order to ensure that the soft beads 5 are prevented from being scratched on an optical disk or the like, it is important that the average particle diameter of the soft beads 5 is larger than the average thickness of the epoxy resin matrix layer 4. As a result, as shown in FIG. 1, since the cross-sectional shape of the resin film 3 becomes a fine uneven shape in which the soft beads 5 are convex, the optical disk and the epoxy-based resin matrix layer 4 The contact area is greatly reduced, and the contact area works as a soft bead and soft bead 5 force S cushioning material, so it is possible to ensure the prevention of wrinkling on optical discs, etc.

[0037] Here, when the average particle size force of the soft beads 5 exceeds 5 times the average thickness of the epoxy resin matrix layer 4, most of the soft beads 5 are solidified in the epoxy resin matrix layer 4. Since it becomes difficult to determine, the effect which prevents the sliding wrinkle to an optical disk etc. falls. If the average particle size of the soft beads 5 is less than 1.1 times the average thickness of the epoxy resin matrix layer 4, the particle size is small! 4 The effect of preventing sliding wrinkles on optical discs is reduced. Therefore, the average particle diameter of the soft beads 5 should be 1.1 to 5 times the average thickness of the epoxy resin matrix layer. It is more preferable that the average thickness of the epoxy resin matrix layer 4 is 1.5 times or more and 4 times or less! /.

[0038] If the average particle diameter of the soft beads 5 and the average thickness of the epoxy-based resin matrix layer 4 are maintained in such a relationship, it is possible to prevent sliding wrinkles from entering an optical disk or the like. However, if the above relationship is maintained, even if necessary, use soft beads 5 having a larger particle diameter than necessary. Then, since the average thickness of the epoxy resin matrix layer 4 must be increased, the resin film 3 becomes thicker than necessary, and it is not economical. It is industrially difficult to control the relationship between the average particle diameter of the soft beads 5 and the average thickness of the epoxy resin matrix layer 4. Therefore, the average particle diameter of the soft bead 5 should be about 5 to 30 m, and the average thickness force of the epoxy-based resin matrix layer 4 should be 3 / zm to 10 / zm. preferable. The average thickness of the epoxy resin matrix layer 4 is a value obtained by measuring the weight of the resin film 3 per unit area and converting the specific gravity to 1.

[0039] The particle size of the soft beads 5 actually has a distribution. For example, the particle size distribution of beads with an accumulated volume of 50% and a particle size of about 8 μm is distributed from a minimum of about 1 μm to a maximum of about 20 μm. Mick beads (registered trademark) particle size distribution (synonymous with particle size distribution)). Therefore, in the present invention, the average particle diameter is adopted as an index of the particle diameter of the soft beads 5. The average particle diameter is an integrated volume 50% particle diameter measured with a laser diffraction particle size distribution analyzer or the like in a state where the soft beads 5 are dispersed in water.

[0040] (Percentage of fluorine concentration in the resin film)

When the epoxy resin matrix layer 4 contains a fluorine additive, the ratio of fluorine concentration at the outermost surface of the resin film 3 is expressed by the following formula (1)

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

The ratio of the fluorine concentration is calculated to be 10% or less, more preferably 7% or less.

[0041] Here, the ratio of fluorine concentration was measured and converted by ESCA (X-ray photoelectron analyzer), fluorine mass%, carbon mass%, oxygen mass% and nitrogen mass% of the outermost surface of resin film 3. Using the above equation (1). Note that the outermost surface of the coating here is the surface on the side to which the adhesive tape adheres, that is, the outermost surface of the precoated metal plate 1, and is not the interface between the resin coating 3 and the metal plate 2. .

[0042] Specifically, the ratio of the fluorine concentration on the outermost surface of the coating is the ratio of the precoated metal plate 1 This is a value based on the mass% of each element obtained when the element was analyzed by ESCA while digging from the surface to the inside by argon sputtering or the like, and the argon sputtering time was zero. That is, since the surface is not dug at all by argon sputtering or the like, it can be defined as the state of the outermost surface.

[0043] When the epoxy resin matrix layer 4 contains a predetermined amount or more of a fluorine additive, the ratio of the fluorine concentration on the outermost surface of the film may exceed 10%. In this case, since the ratio of fluorine present on the outermost surface of the resin film 3 and contributing to the peelability of the adhesive becomes too high, the peel strength when attaching parts with a double-sided adhesive tape increases, A stable adhesive force cannot be maintained.

[0044] (Corrosion resistant coating)

Next, the precoated metal plate 1 of the present invention may be provided with a corrosion-resistant film (not shown) between the metal plate 2 and the epoxy resin matrix layer 4 including the soft beads 5. By forming the corrosion-resistant film, corrosion resistance is imparted to the precoated metal plate 1 and adhesion between the metal plate 2 and the resin film 3 is improved. The structure of the corrosion resistant film is, for example, as follows.

[0045] The corrosion-resistant film is a conventionally known corrosion-resistant film containing Cr or Zr as a component. Alternatively, a coating-type zirconium film or the like can be used as appropriate. 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 2 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, when the adhesion amount exceeds 50 mgZm ² , cracking (peeling) occurs in the corrosion-resistant film itself in press molding or the like, making it difficult to maintain high corrosion resistance for a long period of time.

[0046] 2. Manufacturing method of pre-coated metal sheet

The method for producing a precoated metal sheet according to the present invention includes a step of applying an epoxy-based paint in which soft beads are dispersed to the surface of a metal plate, and baking the applied epoxy-based paint to form a resin film. A method of combining the process is known. Hereafter, each process And explain.

[0047] The first step is to apply an epoxy-based paint in which soft beads are dispersed on the surface of the metal plate. The epoxy-based paint used is composed of a main agent composed of bisphenol A type epoxy resin and urea. It is preferable that a curing agent having a compound-based compound or phenol-based compound is dissolved in an organic solvent. In addition, it is desirable to add a lubricant such as natural wax, petroleum wax, synthetic wax, or a mixture thereof in addition to the soft bead, which is an essential component, to epoxy-based paints. For a typical fluorine-based lubricant, the ratio of fluorine concentration on the outermost surface of the resin film is expressed by the following formula (1)

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

It is preferable to use it within the range where the ratio of fluorine concentration does not exceed 10%, and it is more preferable to use within the range not exceeding 7%. Furthermore, additives such as dyes and pigments for coloring purposes, various inorganic fillers for improving the hardness of the grease film, and conductive additives, and conductive additives are not included in the content of the claims of the present invention. It is possible to add free as much as possible.

[0048] Examples of the dispersion treatment method of the urethane beads in the epoxy paint include ultrasonic treatment, stirring treatment using a magnetic stirrer impeller, stirring treatment using a homogenizer, attritor, ball mill, bead mill, etc. Is mentioned.

[0049] Application of the epoxy paint may be performed by any method such as brush, roll coater, curtain flow coater, roller force single-coater, electrostatic coater, blade coater, die coater, etc. It is more preferable to use a roll coater that is uniform and easy to work. The coating amount takes into consideration the transport speed of the metal plate, the rotation direction and the rotation speed of the roll coater, etc. so that an epoxy resin matrix layer with an average thickness of 3 to: LO m is formed on the surface of the metal plate And set as appropriate.

[0050] Prior to the application of the epoxy paint, a degreasing step for degreasing the surface of the metal plate may be provided. For example, an alkaline aqueous solution is sprayed on the surface of the metal plate, and then washed with water to degrease the surface of the metal plate. Furthermore, as described above, the metal plate and the epoxy resin film When a corrosion resistant film is provided between them, the corrosion resistant film can be formed by spraying a chemical conversion solution containing chromium ions or the like on the surface of the metal plate following the degreasing step.

[0051] Next to the step of applying the epoxy paint to the metal plate is a step of forming a resin film (epoxy resin matrix layer including soft beads) from the applied epoxy paint, The applied epoxy paint is baked to cure (crosslink) the epoxy paint. Then, the epoxy coating is cured (cross-linked), whereby the resin film is firmly bonded to the metal plate. Furthermore, it is fixed to the soft bead strength S fluorine-based resin matrix layer.

[0052] Although the baking temperature does not affect the scratch resistance of the coated optical disk or the adhesive property of the double-sided adhesive tape, if the baking temperature is less than 200 ° C, the epoxy coating is cured ( (Crosslinking) becomes insufficient, and when the baking temperature exceeds 300 ° C, the epoxy paint is thermally deteriorated (decomposed), so 200 ° C or more and 300 ° C or less are preferable. 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 hardening furnace.

Example

[0053] Next, in the precoated metal sheet according to the present invention, the type and average thickness of the matrix layer of the resin film, the type of beads dispersed in the matrix layer, and hardness (compression strength at 10% deformation) When the ratio of surface fluorine concentration adjusted by the content, average particle size, and amount of added tetrafluoroethylene was changed, it was confirmed that the optical discs were not wrinkled, the adhesive peeled, and the paintability. Examples and comparative examples will be described.

[0054] (Examples 1 to 12)

As Examples 1 to 12, precoated metal sheets were produced according to the above production method. Each configuration of the pre-coated metal sheet is as follows.

(Metal plate)

An aluminum alloy plate of thickness 0.5mm and JIS standard 5052-H34 was used. (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.

(Resin film)

Apply an epoxy-based paint in which soft beads with a compressive strength at the time of deformation of 10% specified in the present invention and tetrafluoride-tylene powder are dispersed on the outermost surface of the phosphate chromate film, and bake temperature (peak temperature of the metal plate) Baking treatment was performed at 250 ° C to form a resin film (fluorine-based resin matrix layer). Here, urethane beads were used as the soft beads. In Example 10 where the surface fluorine concentration was 0%, tetrafluorinated styrene powder was not added.

[0055] Here, as the epoxy paint, a one-pack type epoxy urea paint in which a main agent composed of bisphenol A type epoxy resin and a curing agent composed of a urea compound was dissolved in an organic solvent was used. . This time, Dainippon Ink & Chemicals, Inc. used, but paints with similar composition are available from Kansai Paint and Nippon Paint.

[0056] (Comparative Examples 1 to 12)

As a control for Examples 1-12, precoated metal sheets of Comparative Examples 1-12 were prepared. Comparative Example 1 used an epoxy-based paint containing no soft beads, and Comparative Examples 2 and 3 had a soft bead content not satisfying the scope of the claims of the present invention. Comparative Examples 4 and 5 Indicates that the relationship between the average particle diameter of the soft beads and the average thickness of the epoxy resin matrix layer does not satisfy the scope of the claims of the present invention, and Comparative Examples 6 and 7 show the amount of applied force of the tetrafluorinated styrene powder. As a result, the ratio of the fluorine concentration on the outermost surface of the film does not satisfy the claims of the present invention, but Comparative Examples 8 and 9 use a different type of resin matrix layer from the epoxy type. Comparative Example 10 uses a different type of resin matrix layer from the epoxy type, and the fluorine concentration ratio does not satisfy the claims of the present invention, and Comparative Examples 11 and 12 are the present invention. Beads that do not have compressive strength at the time of 10% deformation specified (That is, it's not soft !, beads).

[0057] Next, with respect to the pre-coated metal sheet of Examples 1-12 and Comparative Examples 1-12, the ratio of the fluorine concentration on the outermost surface of the resin film was measured, and the results are shown in Table 1. It was. In addition, the measuring method of each characteristic was as follows. [0058] (Percentage of fluorine concentration)

The outermost surface of the resin film was measured with ESCA (manufactured by Shimadzu Corporation) to obtain atomic% of 4 elements of fluorine, carbon, oxygen and nitrogen. These atomic% were converted into mass% using the atomic weight of each element. Using this fluorine mass% (F), carbon mass% (C), oxygen mass% (O) and nitrogen mass% (N), the ratio of fluorine concentration (A (%) ) Was calculated.

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

[0059] Here, the outermost surface of the coating refers to a state where the surface of the pre-coated metal plate prepared above is measured as it is, that is, in a state where the argon sputtering time is zero.

[0060] Further, a resin film composed of an epoxy resin matrix layer and beads is a non-uniform film when viewed microscopically. Therefore, when analyzing with ESCA, if the area of the analysis surface is made too small, information indicating that the epoxy resin matrix layer is locally rich, or conversely, that the region is locally rich in the bead force S is obtained. As a result, the fluorine concentration ratio may vary at each measurement timing. Therefore, the area of the analysis surface was set to 3 mmφ so that average information on the resin film could be obtained. Here, it goes without saying that 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.

[0061] Next, the anti-sticking property and adhesive tape adhesiveness of the precoated metal plates of Examples 1 to 12 and Comparative Examples 1 to 12 to the optical disk were measured and evaluated. The results are shown in Table 1. In addition, the measurement and evaluation method of wrinkle prevention and adhesive tape adhesiveness were as follows.

[0062] (Anti-sticking property to optical disk)

The recording surface of a commercially available optical disk was brought into contact with the surface of the precoated metal sheet, and the surface of the optical disk was visually evaluated after being rubbed back and forth 10 times while gently pressing with a finger. 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 determination of the sample was taken as the determination result of the anti-fouling property of the pre-coated metal plate. However, wrinkles generated by rubbing the edge of the optical disk were excluded, and only the sliding wrinkles between the resin film surface and the optical disk recording surface were determined.

Judgment is “◎” for the excellent anti-sticking property, “◯” for the good anti-sticking property, “△” for the slightly poor anti-sticking property, and poor anti-sticking property. The thing was called "X".

[0063] (Adhesive tape adhesive) The adhesive tape peel strength was measured by the 180 degree peel test specified in JISK6854-2. As the adhesive tape, a commercially available double-sided adhesive tape (double-sided adhesive tape manufactured by SLIONTEC Corporation, product number 5460, tape width 6 mm) was used. As measurement conditions, a precoated metal plate with a length of lOOmm x width of 60 mm and an adhesive tape with a length of lOOmm x width of 6 mm were used, and the peel strength was 50 mmZmin. The adhesive evaluation in Table 1 shows that the adhesive tape peel strength is 2.0N / 6mm or more, “◯” is excellent, and the adhesive tape is less than NZ6mm, “X” is poor adhesive. It was.

[table 1]

(Note) Underlined in the table indicates that the scope of claims of the present invention has not been achieved.

[0065] As shown in Table 1, each of the precoated metal plates of Examples 1 to 12 had an adhesive tape peeling strength of more than 2.0 NZ6 mm, exhibiting excellent adhesive tape adhesion, and preventing wrinkles on the optical disc The property was also good or excellent. Further, as the content of the urethane beads increases, the tendency to improve wrinkling is recognized. When the content is 5% by mass or more, it is generally good, and when the content is 10% by mass or more, excellent wrinkle is achieved. The anti-sticking property was shown.

[0066] On the other hand, all of the precoated metal plates of Comparative Examples 1, 2, 4, 5, 11, and 12 had adhesive tape peeling strength exceeding 2.0 N / 6 mm and had excellent adhesive tape adhesive strength. It was inferior in the anti-sticking property to the disc. In addition, Comparative Examples 6 to 10 are all excellent in preventing the optical disc from being wrinkled! / Soiled, but the adhesive tape peel strength was below 2.0NZ6mm, and the adhesive tape peelability was poor. Furthermore, in Comparative Example 3, the soft bead content was 60% by mass, exceeding the range of the present invention, so that the viscosity of the epoxy paint increased remarkably and the paintability was difficult.

Claims

The scope of the claims

[1] 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 epoxy resin matrix layer and the epoxy resin matrix layer And a soft bead with a compressive strength of 10 MPa or less when deformed by 10% single bead by micro compression test,

The content of the soft beads is 5% by mass or more and 50% by mass or less with respect to the epoxy resin matrix layer.

The precoated metal sheet, wherein an average particle diameter of the soft beads is 1.1 times or more and 5 times or less of an average thickness of the epoxy resin matrix layer.

[2] The precoated metal sheet according to [1], wherein the soft beads are urethane beads.

[3] The epoxy-based resin matrix layer is a film in which a main agent composed of bisphenol A-type epoxy resin and a curing agent having a urea-based compound or a phenol-based compound is cross-linked by heat. The precoated metal sheet according to claim 1 or 2.

[4] The precoated metal sheet according to [1] or [2], wherein the epoxy-based resin matrix layer contains a fluorine-based lubricant as an additive imparting lubricity.

[5] The precoated metal sheet according to [4], wherein the fluorine-based lubricant is tetrafluoroethylene.

[6] The amount of the fluorine-based lubricant added is the ratio of the fluorine concentration on the outermost surface of the resin film, expressed by the following formula (1)

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

5. The precoated metal sheet according to claim 4, wherein the fluorine concentration ratio is within a range of 10% or less when calculated in (5).

[7] The pleco according to claim 1 or 2, wherein an average particle diameter of the soft beads is 1.5 times or more and 4 times or less of an average thickness of the epoxy resin matrix layer. one G metal plate.

[8] The precoated metal according to claim 1 or 2, wherein the content of the soft beads is 10% by mass or more and 40% by mass or less with respect to the epoxy resin matrix layer. Board.

[9] The precoated metal sheet according to [1] or [2], wherein a corrosion-resistant film is provided between the metal sheet and the resin film.

[10] The precoated metal plate according to claim 1 or 2, wherein the metal plate is an aluminum plate or an aluminum alloy plate.