JP3846807B1 - Pre-coated metal plate and manufacturing method thereof - Google Patents

Abstract

[PROBLEMS] To have an excellent moldability and appearance, and in an application in which an adhesive is used in combination, the adhesive is difficult to adhere, is not easily contaminated with dirt and oil, and even when an optical disk or the like comes into contact, the surface thereof is brazed. Provided are a pre-coated metal plate having difficult characteristics and a method for producing the same.
A pre-coated metal plate 1 comprising a metal plate 2, a resin film 3 comprising a fluorine-based resin matrix layer 4 and urethane beads 5 dispersed therein, wherein the urethane beads 5 have a content ratio thereof. 5 mass% or more and 50 mass% or less, the average particle diameter is 1.1 times or more and 5 times or less of the average thickness of the fluororesin matrix layer 4, and the ratio of the fluorine concentration of the resin film 3 is expressed by the following formula (1 ) Is 15% or more at the outermost surface of the film and 15% or less inside the film.
A (%) = {F / (F + C + O + N)} × 100 (1), where A is the ratio of fluorine concentration, F is fluorine mass%, C is carbon mass%, O is oxygen mass%, N Is nitrogen mass%.
[Selection] Figure 1

Description

  The present invention relates to a pre-coated metal plate used for various uses such as an outer plate material and a structural member such as a household electric product and an in-vehicle component for an automobile, as well as a building material and a roof material, and a manufacturing method thereof.

  Metal thin plate materials represented by steel plates, aluminum plates, and aluminum alloy plates have both high strength and workability. By applying various processing, various materials such as household electrical products, automotive in-vehicle parts, and building materials can be used. Applied to usage. The processed metal plate used for these applications may be subjected to surface treatment for the purpose of improving the appearance and corrosion resistance. For this surface treatment, the post-coating method that has been performed after processing a metal plate into a predetermined shape has been the mainstream, but recently, for the purpose of improving the work environment, simplifying the process and reducing costs, etc. A pre-coating method in which a pre-coated metal plate that has been previously surface-treated on a metal plate is formed into a predetermined shape and used is also fixed. Furthermore, in recent years, such pre-coated metal sheets have various functions such as fingerprint resistance, scratch resistance, ground connection, heat dissipation, heat insulation, antibacterial properties, etc. in order to meet the diversification and upgrading of products and equipment. A functional pre-coated metal sheet having a surface roughness has been developed and is widely used.

Pre-coated metal sheets are molded with surface coating applied, so the coating film not only requires excellent moldability, but the appearance after press 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 that is coated with 5 to 60% of a coating having a thickness of 0.5 to 10 μm and has excellent formability and scratch resistance with a friction coefficient controlled to 0.15 or less.

The pre-coated metal plate described in Patent Document 1 is made of an aluminum alloy plate, but pre-coated metal plates made of aluminum are generally well-received in applications where lightness is required. Covers and structural members such as covers for optical disk drives for automobiles, frames and back covers for liquid crystal display devices, automotive electronic components such as ECUs (Electronic Control Units), car stereos, car navigation systems, and optical disk auto changers Has also been used. 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, personally edited music CDs etc. The production of optical discs is also increasing. Also, as shown in FIG. 4A, such a self-made optical disc 10 may be used in a state where an identification label L for identification is adhered to the surface of the optical disc D.
Japanese Patent No. 3338156 (paragraph numbers 0008 to 0017)

  However, in applications where an adhesive such as the identification label L may be inserted into the apparatus as in the examples of the optical disk drive and the optical disk autochanger described above, a part of the identification label L is caused by the heat of the apparatus. It is necessary to prepare for the risk that the peeled and exposed adhesive portion Ln will subsequently reattach to each part in the apparatus.

  As one of the techniques for preventing such danger, it is considered effective to perform a surface treatment on which a sticky substance (identification label L) is likely to adhere, so that the sticky substance does not easily adhere. For example, as shown in FIG. 4B, in the example of the optical disk drive 20, the area adjacent to the self-made optical disk 10, such as on the tray 21 on which the self-made optical disk 10 is placed, or inside the cover 22 that covers the self-made optical disk 10. It is considered that the larger the member, the greater the risk of adhesion of an adhesive. Therefore, it is considered effective for avoiding the danger to pre-treat the pre-coated metal plate that is processed into these parts in advance so that such a sticking material is difficult to adhere. In addition, the property that such adhesives are difficult to adhere actually has the property of repelling various substances such as oil and dirt as well as adhesives, so building materials, automotive in-vehicle parts, indoor equipment, etc. It is also expected that the frequency of maintenance can be reduced for long-term use.

  In order to meet the above requirements, the present inventor forms a resin film on the surface of a metal plate by applying and baking a fluorine-based paint combining a specific fluorine resin and a curing agent, and optimizing the baking conditions. By increasing the fluorine concentration on the outermost surface of the resin film, the non-adhesiveness of the adhesive is ensured, and at the same time, the fluorine concentration inside the film is lowered to improve the adhesion between the metal plate and the resin film. Invented a pre-coated metal plate excellent in non-adhesive properties and a method for producing the same (Japanese Patent Application No. 2005-90137).

  As shown in FIG. 4B, the conventional optical disk drive 20 is generally a drawer system in which the tray 21 on which the self-made optical disk 10 is set enters and exits the optical disk drive 20 when the self-made optical disk 10 is put in and out. Met.

  On the other hand, although not shown, a slot-in type optical disc drive has recently been developed in which a tray for setting an optical disc does not go in and out, and only the optical disc is inserted and inserted into an opening of the optical disc drive. In such a slot-in type optical disc drive, the optical disc enters and exits the inner surface of the optical disc drive cover, so that the optical disc surface rubs against the inner surface of the optical disc drive cover when the optical disc enters and exits, and sliding wrinkles enter. There is a problem that it is easy.

  In order to prevent wrinkles from entering the surface of the optical disc when the optical disc enters and exits, conventionally, wrinkle prevention processing is performed on a portion where the optical disc is likely to slide by a technique such as spray coating. However, such a method requires processing each press-molded optical disc drive cover molded product one by one, so there are problems such as complicated processes, poor productivity, and extremely high cost. A point has been pointed out. Therefore, it is expected that the process is simplified, the productivity is improved, and the cost is reduced by applying the anti-wrinkle treatment to the aluminum plate before forming.

  The present invention has been made in order to solve the above-mentioned problems, and its purpose is to have an excellent formability and appearance that are fundamental to a pre-coated metal plate to be used after forming, and to use an adhesive together. It is intended to provide a pre-coated metal plate having a characteristic that it is difficult for an adhesive to adhere, dirt and oil to adhere, and it is difficult to scratch the surface of an optical disk, etc., and its manufacturing method. .

In order to solve the above problems, the invention of claim 1 is a pre-coated metal plate comprising a metal plate and a resin film formed on the surface thereof, wherein the resin film is a fluorine-based resin matrix layer, and the fluorine-based material. Urethane beads dispersed in a resin matrix layer, wherein the content of the urethane beads is 5% by mass or more and 50% by mass or less with respect to the fluororesin matrix layer, and the average particle size of the urethane beads When the diameter is 1.1 times to 5 times the average thickness of the fluororesin matrix layer and the ratio of the fluorine concentration on the outermost surface of the resin film is calculated by the following formula (1), The ratio is 15% or more, and when the ratio of fluorine concentration inside the resin film is calculated by the following formula (1), the ratio is 15% or less. It is intended.
A (%) = {F / (F + C + O + N)} × 100 (1)
In the formula (1), A is a fluorine concentration ratio, F is fluorine mass%, C is carbon mass%, O is oxygen mass%, and N is nitrogen mass%.

  By configuring in this way, even if an optical disk or the like comes into contact with the urethane beads, the cushion material is used as a cushioning material by controlling the content and average particle size of the urethane beads dispersed in the fluororesin matrix layer (resin film). Therefore, the resin film can prevent wrinkles from entering the surface of the optical disk or the like. Moreover, since fluorine concentrates on the outermost surface of the film on the surface of the resin film, the peel strength of the adhesive to the resin film can be kept low. At the same time, since the fluorine concentration is kept low inside the film excluding the outermost surface of the film, the fluorine-based resin film is firmly bonded to the metal plate without forming a resin-based primer layer or an adhesive layer. Furthermore, since the fluororesin matrix layer contains urethane beads having an average particle size larger than the average thickness of the fluororesin matrix layer, the surface of the resin film becomes a surface with fine irregularities, and the adhesive is a resin. When adhering to the film, a minute air layer is formed on the fine irregularities, and the contact area between the adhesive and the resin film decreases. As a result, the peel strength of the adhesive with respect to the resin film can be kept low.

The invention according to claim 2 is that the fluororesin matrix layer of the resin film comprises a fluororesin having at least one of a hydroxyl group, a carboxyl group and an amino group and an isocyanate compound having two or more isocyanate groups. It is configured as a precoated metal plate bonded with at least one chemical bond among a bond, an acid amide bond and a urea bond.
If comprised in this way, since the molecule | numerator of a fluorine-type resin matrix layer crosslinks by these chemical bonds and forms a three-dimensional network structure, a resin film adhere | attaches a metal plate still more firmly.

The invention of claim 3 is configured as a precoated metal plate in which the average particle diameter of the urethane beads is 1.5 to 4 times the average thickness of the fluororesin matrix layer.
If comprised in this way, the effect | action as a cushion material of a urethane bead will improve, and it can further prevent that a wrinkle enters into the surface of an optical disk etc. by a resin film.

The invention of claim 4 is configured as a pre-coated metal plate in which the content of the urethane beads is 10% by mass or more and 40% by mass or less with respect to the fluorine-based resin matrix layer.
If comprised in this way, the effect | action as a cushion material of a urethane bead will improve, and it can further prevent that a wrinkle enters into the surface of an optical disk etc. by a resin film. In addition, when applying a fluorine-based paint having urethane beads dispersed on the surface of the metal plate in order to form a resin film, the viscosity of the fluorine-based paint is adjusted to a predetermined range, and the paintability is improved.

The invention of claim 5 is configured as a pre-coated metal plate provided with a corrosion-resistant film between the metal plate and the resin film.
If comprised in this way, while the corrosion resistance of a precoat metal plate will improve, a resin film will adhere more firmly to a metal plate.

According to a sixth aspect of the present invention, the metal plate is configured as a precoated metal plate which is an aluminum plate or an aluminum alloy plate.
If comprised in this way, weight reduction can be achieved compared with the case where another metal plate is used.

  Invention of Claim 7 is provided with the metal plate and the resin film formed in the surface as a manufacturing method of a precoat metal plate, The manufacture of the precoat metal plate as described in any one of Claim 1 thru | or 6 In the method, a first step of applying a fluorine-based paint in which urethane beads are dispersed to the surface of the metal plate; and a step of baking the fluorine-based paint at 200 ° C. or higher and 280 ° C. or lower to form the resin film. The procedure includes two steps.

  According to such a procedure, the ratio of fluorine concentration in the resin film is concentrated on the outermost surface of the resin film by the baking treatment at a predetermined temperature, and can be kept low inside the resin film. The peel strength of the object can be kept low. Further, the resin film is firmly bonded to the metal plate. Furthermore, since urethane beads are fixed in the resin film and act as a cushioning material, wrinkles can be prevented from entering the surface of an optical disk or the like.

  According to the precoated metal plate according to the present invention, the resin film formed on the surface of the metal plate is not only excellent for the precoated metal plate to be molded and used, but has excellent formability and appearance as well as an adhesive. Even if it is used for applications, it can be combined with the properties that adherents are hard to adhere and dirt and oil are difficult to adhere, and the resin film is firmly attached to the metal plate without using the resin primer layer or adhesive layer. Can be glued. In addition, by optimizing the content and average particle size of the urethane beads dispersed in the resin film (fluorinated resin matrix layer), the resin film surface and Even when the surface of the optical disk slides, wrinkles can be prevented from entering the optical disk.

  Further, according to the method for producing a precoated metal sheet according to the present invention, the precoated metal sheet having a small adhesive peel strength and excellent anti-wrinkle property to an optical disk or the like can be formed without forming a resin primer layer or an adhesive layer. Manufactured. Further, by applying the wrinkle prevention treatment to the aluminum plate before the forming process in advance, the wrinkle prevention treatment can be performed with a simple process, high productivity, and low cost as compared with the case where the wrinkle prevention treatment is performed after the forming process.

Hereinafter, embodiments of the present invention will be described in detail.
1. Pre-coated metal plate As shown in FIG. 1, a pre-coated metal plate 1 of the present invention is formed on the surface of a metal plate 2 that is a base material and the metal plate 2, and the fluorine concentration in the outermost surface of the film and inside the film is a predetermined value. And the resin film 3 controlled to be Among these, the resin film 3 is composed of a fluorine-based resin matrix layer 4 and urethane beads 5 dispersed in the fluorine-based resin matrix layer 4, and the content and average particle diameter of the urethane beads 5 have predetermined values. It is controlled to become. Here, the surface means at least one surface of the metal plate 2. Next, each configuration will be described.

(1) Metal plate There is no restriction | limiting in particular in the metal plate 2 used by this invention, In addition to the most general cold-rolled steel plate, hot-dip galvanized steel plate, electrogalvanized steel plate, alloyed hot-dip galvanized steel plate and copper-plated steel plate Various plated steel plates such as tin-plated steel plates, alloy steel plates such as stainless steel, aluminum or aluminum alloy plates, and non-ferrous metal plates such as copper or copper alloy plates are all applicable. Here, aluminum 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. In particular, Al—Mg alloys represented by 5052 and 5182 specified in JIS are more preferable.

(2) Resin film (ratio of fluorine concentration in resin film)
The resin film 3 is characterized in that when the ratio of the fluorine concentration on the outermost surface of the resin film 3 is calculated by the following formula (1), the ratio is 15% or more, and at the same time, the same formula (1 ), The ratio of the fluorine concentration inside the resin film 3 is 15% or less.
A (%) = {F / (F + C + O + N)} × 100 (1)
In the formula (1), A is a fluorine concentration ratio, F is fluorine mass%, C is carbon mass%, O is oxygen mass%, and N is nitrogen mass%.

  Here, the ratio of the fluorine concentration was measured and converted by ESCA, using the above-mentioned formula (% by mass of fluorine, carbon mass, oxygen mass and nitrogen mass% of the outermost surface of the resin film 3 and the interior of the film). Calculated in 1). The outermost surface of the film referred to here is the surface on the side to which the adhesive (identification label L shown in FIG. 4 or the like) adheres, that is, the outermost surface of the pre-coated metal plate 1, and the resin film 3 and the metal plate 2 It's not the interface. Further, the inside of the film means a portion of the resin film 3 excluding the surface (outermost surface) that adheres to the adhesive and the surface that adheres to the metal plate 2, and preferably the inside of the film is the outermost film of the resin film 3. From the surface, it means a part of 1/2 to 1/3 of the film thickness in the thickness direction.

  More specifically, when each elemental analysis is performed by ESCA while digging by argon sputtering from the surface of the precoated metal plate 1 to the inside, the ratio of the fluorine concentration on the outermost surface of the film is the argon sputtering time. It is a value based on the mass% of each element obtained in the state of zero. That is, since the surface is not dug at all by argon, it can be defined as the state of the outermost surface. On the other hand, if argon sputtering is continued, the surface is dug in proportion to the argon sputtering time, so that the longer the argon sputtering time, the more the internal element state is shown. Since the components of the metal plate 2 begin to appear when digging to some extent, the argon sputtering time in which the elemental composition of the metal plate 2 exceeds 50% of the whole is defined as the interface between the resin film 3 and the metal plate 2. Assuming that the argon sputtering time to reach this interface is “T”, the inside of the coating handled in this case, that is, the portion of 1/2 to 1/3 of the coating thickness from the outermost surface of the resin coating 3 to the thickness direction. The ratio of the fluorine concentration is defined as a value based on the mass% of each element obtained when the argon sputtering time is ½ to 上 記 of the above “T”.

  As in the present invention, the resin film 3 composed of the fluororesin matrix layer 4 and the urethane beads 5 is a non-uniform film when viewed microscopically. Therefore, when analyzing by ESCA, if the area of the analysis surface is too narrow, information on the part where the fluororesin matrix layer 4 is locally rich or the part where the urethane beads 5 are locally rich can be obtained. Therefore, in this case, the ratio of the fluorine concentration may vary at each measurement timing. Therefore, in the present invention, the measured value when the area of the analysis surface is 3 mmφ is used so that average information of the resin film can be obtained.

  As shown in a comparative example to be described later, when the crosslinking reaction of the fluororesin matrix layer 4 is insufficient or when thermal degradation (decomposition) occurs, the ratio of the fluorine concentration on the outermost surface of the film is less than 15%. It may become. In this case, since the ratio of fluorine existing on the outermost surface of the resin film 3 and relating to the peelability of the adhesive is small, the peel strength of the adhesive with respect to the resin film 3 is increased, and dirt and oil are easily attached. Become. On the other hand, if the ratio of the fluorine concentration inside the film exceeds 15%, the resin film 3 is firmly adhered to the surface of the metal plate 2 without any treatment such as forming a resin primer layer or an adhesive layer. I can't do that.

(2-1) Fluorine Resin Matrix Layer It is desirable that the fluorine resin matrix layer 4 has a cross-linked structure in the molecule as a result of the reaction between the fluorine resin as the main agent and the curing agent. Further, the combination of the main agent and the curing agent includes a main agent which is a fluororesin having at least one of a hydroxyl group, a carboxyl group and an amino group, and an isocyanate having two or more isocyanate groups, preferably three or more isocyanate groups. A compound obtained by bonding (crosslinking) a curing agent which is a compound with at least one chemical bond among urethane bond, acid amide bond and urea bond is preferable. As a result, a stable cross-linked structure is formed in the fluorine-based resin matrix layer 4, and the fluorine-based resin matrix layer 4 (resin film 3) adheres more firmly to the metal plate. As a hydroxyl group, an alcohol-based hydroxyl group and a phenol-based hydroxyl group as well as derivatives that react with an isocyanate group fall under this category in a broad sense. As the carboxyl group, not only a carboxyl group alone but also a derivative that reacts with an isocyanate group such as a dehydrated carboxyl group is applicable. Similarly, for amino groups, all derivatives that react with isocyanate groups are included in the present invention. The degree of cross-linking of the cross-linked fluororesin matrix layer 4 is preferably 80% or more in terms of the gel content defined in JISK6796 which is an index of the degree of cross-linking.

(2-2) Urethane beads In order to apply the pre-coated metal plate 1 to a portion that slides directly with an optical disk or the like, it is necessary to prevent wrinkles from entering the optical disk or the like by sliding. Here, in order to prevent wrinkles from entering the optical disk or the like, it is indispensable to make the resin film 3 soft. In general, methods for softening the resin include a method for lowering the glass transition temperature of the resin and a method for suppressing a crosslinking reaction between the resin and the curing agent. In order to effectively soften the resin film 3, it is most effective to soften the matrix resin which is the main component of the resin film 3, and the resin film 3 can be obtained by actually using these techniques for the matrix resin. Can be softened.

  However, if the softening of the resin film 3 is advanced by these methods, the tackiness of the resin film 3 appears as a side effect, so that the adhesion of the adhesive (the identification label L, see FIG. 4) to the resin film 3 is prevented. The problem arises that damage is lost. On the other hand, when the resin film 3 does not soften the matrix resin, but soft fine particles, that is, urethane beads 5 are added to the resin film 3 (fluorinated resin matrix layer 4), the glass transition temperature of the matrix resin is lowered. The entire resin film 3 can be softened without suppressing the crosslinking reaction. Therefore, it is possible to ensure the anti-fouling property to the optical disc or the like without causing a tack that impedes the adhesion preventing property of the adhesive (the identification label L, see FIG. 4) to the resin film 3. Examples of the urethane beads 5 include Sanyo Kasei's Meltex (registered trademark), Dainichi Seika's Dimic beads (registered trademark), Negami Kogyo Art Pearl (registered trademark), and the like.

(Content of urethane beads: 5% by mass or more and 50% by mass or less)
In order to enhance the prevention of wrinkling on an optical disk or the like, it is preferable that the content of the urethane beads 5 is larger than that of the fluororesin matrix layer 4. If the content rate of the urethane beads 5 is less than 5% by mass, the amount of the urethane beads 5 fixed in the fluororesin matrix layer 4 is small, the action as a cushioning material is lowered, and the anti-sticking property is inferior. In addition, when the content of the urethane beads 5 is increased, the viscosity of the paint in which the urethane beads 5 are dispersed increases, and therefore it is assumed that the paint is applied to the metal plate 2 by roll coating or the like. However, paintability with a uniform film thickness decreases. Furthermore, since the ratio of the fluorine-based resin matrix layer 4 occupying the resin film 3 is reduced more than necessary, the ratio of the fluorine concentration on the outermost surface of the film is less than 15%, and the adhesion preventing property of the adhesive (identification label L) is also reduced. . For the above reasons, the content of the urethane beads 5 is set to 5% by mass or more and 50% by mass or less with respect to the fluororesin matrix layer 4. Moreover, in order to ensure the anti-fouling performance at a high level, the content of the urethane beads 5 is preferably 10% by mass or more, and in order to ensure stable paintability, the content of the urethane beads 5 is It is preferable that it is 40 mass% or less.

(Average particle diameter of urethane beads: 1.1 to 5 times the average thickness of the fluororesin matrix layer)
In order to ensure that the urethane beads 5 are prevented from being scratched on an optical disk or the like, it is important that the average particle diameter of the urethane beads 5 is larger than the average thickness of the fluororesin matrix layer 4. As a result, as shown in FIG. 1, the cross-sectional shape of the resin film 3 becomes a fine uneven shape in which the portion where the urethane beads 5 are present is convex, so that the contact area between the optical disk or the like and the fluororesin matrix layer 4 is increased. At the same time, the soft urethane beads 5 act as a cushioning material at the contact portion, so that it is possible to ensure the prevention of wrinkling on an optical disk or the like.

  Here, when the average particle diameter of the urethane beads 5 exceeds 5 times the average thickness of the fluororesin matrix layer 4, most of the urethane beads 5 are not easily fixed in the fluororesin matrix layer 4. Therefore, the effect of preventing sliding wrinkles on the optical disk or the like is reduced. Further, when the average particle diameter of the urethane beads 5 is 1.1 times or less than the average thickness of the fluorine-based resin matrix layer 4, the urethane beads 5 having a small particle diameter are easily embedded in the fluorine-based resin matrix layer 4. Therefore, the effect of preventing sliding wrinkles on the optical disk or the like is reduced. Therefore, the average particle diameter of the urethane beads 5 is 1.1 to 5 times the average thickness of the fluororesin matrix layer. The average thickness of the fluororesin matrix layer 4 is more preferably 1.5 times or more and 4 times or less.

  If the average particle diameter of the urethane beads 5 and the average thickness of the fluororesin matrix layer 4 are maintained in such a relationship, it is possible to prevent sliding wrinkles from entering the optical disk or the like. However, if urethane beads 5 having a particle size larger than necessary are used, the average thickness of the fluororesin matrix layer 4 must be increased. On the contrary, when urethane beads 5 smaller than necessary are used, it is industrially difficult to control the relationship between the average particle diameter of the urethane beads 5 and the average thickness of the fluororesin matrix layer 4. Become. Accordingly, it is desirable to use the urethane beads 5 having an average particle diameter of about 5 to 30 μm, and the average thickness of the fluororesin matrix layer 4 is preferably 3 μm or more and 10 μm or less. The average thickness of the fluororesin 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.

  The particle size of the urethane beads 5 actually has a distribution. For example, the particle size distribution of beads of about 8 μm with a 50% cumulative volume particle size is distributed from a minimum of about 1 μm to a maximum of about 20 μm (Daimic Beads (registered trademark) particle size on the website of Dainichi Seika) 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 urethane beads 5. The average particle diameter is an integrated volume 50% particle diameter measured with a laser diffraction particle size distribution measuring instrument or the like in a state where the urethane beads 5 are dispersed in water.

  Further, as described above, since the average particle diameter of the urethane beads 5 is larger than the average thickness of the fluororesin matrix layer 4, the surface of the resin film 3 is a surface on which fine irregularities are formed. From this, when a pressure-sensitive adhesive adheres to the resin film 3, a minute air layer is formed on the fine irregularities, and the contact area between the pressure-sensitive adhesive and the resin film 3 is reduced. Therefore, the peel strength of the adhesive with respect to the resin film 3 can be kept low.

  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 fluororesin matrix layer 4 including the urethane 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.

(Corrosion resistant coating)
The corrosion resistant coating is a conventionally known corrosion resistant coating containing Cr or Zr as a component, such as a phosphate chromate coating, a chromate chromate coating, a zirconium phosphate coating, a zirconium oxide-based coating, a coating type chromate coating, or a coating type zirconium coating. Etc. 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 mg / m ² , cracking (peeling) occurs in the corrosion-resistant film itself in press molding or the like, and it becomes difficult to maintain high corrosion resistance for a long period of time.

2. Manufacturing method of precoat metal plate The manufacturing method of the precoat metal plate of this invention is the 1st process of apply | coating the fluorine-type coating material which disperse | distributed urethane beads to the surface of a metal plate, and 200 degreeC or more of the apply | coated fluorine-type coating material And a second step of forming a resin film by baking at 280 ° C. or lower. Hereinafter, each step will be described.

(First step)
A process of applying a fluorine-based paint in which urethane beads are dispersed on the surface of a metal plate, and the fluorine-based paint is cured into a fluorine-based resin having at least one of a hydroxyl group, a carboxyl group, and an amino group as a main agent. As the agent, a mixture of an isocyanate compound having 2 or more, preferably 3 or more isocyanate groups, more preferably a blocked isocyanate compound in which an isocyanate group is blocked is preferable. Further, a lubricant such as natural wax, petroleum wax, synthetic wax or a mixture thereof may be added to the fluorine-based paint. Furthermore, additives such as dyes and pigments for the purpose of coloring, various inorganic fillers for improving the hardness and scratch resistance of the resin film, and conductive additives are within the scope of the claims of the present invention. Can be added freely.

  A blocked isocyanate compound is a compound in which an active isocyanate group of an isocyanate compound is stabilized by a blocking agent such as an active hydrogen compound, and is not reactive at room temperature. This blocked isocyanate compound has reactivity due to dissociation of the blocking agent due to heating such as baking treatment, and regeneration of the active isocyanate group. Examples of blocking agents for blocked isocyanate groups include alcohols such as methanol, ethanol, n-propanol and tert-butanol, phenols such as phenol, m-cresol and isooctylphenol and resorcinol, ε-caprolactams, oximes, Examples include active methylene compounds such as acetylacetone, methyl ethyl ketone, and ethylene chlorohydrin, and sodium sulfite. On the other hand, examples of the isocyanate compound having a blocked isocyanate group include toluene diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), polymeric MDI, isophorone diisocyanate and hexamethylene diisocyanate. In addition, polyisocyanates modified with polyhydric alcohols, polyisocyanates with a burette bond or an isocyanate bond, and the like are also included as isocyanate compounds.

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

  Examples of the dispersion treatment method of the urethane beads in the fluorine-based paint include ultrasonic treatment, stirring treatment using a magnet stirrer or impeller stirrer, stirring treatment using a homogenizer, attritor, ball mill, bead mill, and the like.

  Fluorine paint can be applied by any method, such as brush, roll coater, curtain flow coater, roller curtain coater, electrostatic coating machine, blade coater, die coater, etc., but the coating amount is particularly uniform. In addition, it is more preferable to use a roll coater that is easy to work. The coating amount is appropriately set in consideration of the conveyance speed of the metal plate, the rotation direction and the rotation speed of the roll coater, etc. so that a fluorine resin matrix layer having an average thickness of 3 to 10 μm is formed on the surface of the metal plate. To do.

  Prior to application of the fluorine-based paint, a degreasing step for degreasing the surface of the metal plate may be provided. For example, an aqueous alkali solution is sprayed on the surface of the metal plate, and then washed with water to degrease the surface of the metal plate. Further, as described above, when a corrosion-resistant film is provided between the metal plate and the fluorine-based resin film, a chemical conversion treatment solution containing chromium ions or the like is sprayed on the surface of the metal plate after the degreasing step. A corrosion-resistant film can be formed.

(Second step)
This is a process for forming a resin film (fluorine resin matrix layer containing urethane beads) on the surface of the metal plate, and the fluorine-based paint applied in the first process is baked at 200 ° C. or higher and 280 ° C. or lower to obtain a fluorine-based resin. The paint is cured (crosslinked). When the fluorine-based paint is cured (crosslinked), a resin film having a fluorine concentration ratio of 15% or more on the outermost surface of the film and a fluorine concentration ratio of 15% or less inside the film is formed. In addition, the resin film adheres firmly to the metal plate. Here, the baking temperature is the peak temperature of the metal plate. Furthermore, urethane beads are fixed to the fluororesin matrix layer.

  If the baking temperature is less than 200 ° C, curing (crosslinking) of the fluorine-based paint will be insufficient, and if the baking temperature exceeds 280 ° C, the fluorine-based paint will be thermally deteriorated (decomposed). The peel strength of the pressure-sensitive adhesive with respect to the film surface becomes high. The baking time is preferably 20 to 60 seconds. If the treatment time is less than 20 seconds, the baking tends to be insufficient, and if it exceeds 60 seconds, the baking treatment time is too long, and the productivity per hour tends to decrease. In addition, the baking treatment is performed using, for example, a hot air furnace, an induction heating furnace, a near infrared furnace, a far infrared furnace, or an energy beam curing furnace.

  Next, in the pre-coated metal plate according to the present invention, when the content of urethane beads dispersed in the resin film (fluorine-based resin matrix layer) and the average particle diameter are changed, the anti-sticking property and adhesion to an optical disk or the like are changed. The Example which confirmed thing peelability is demonstrated.

(Examples 1-9)
As Examples 1 to 9, precoated metal sheets were produced according to the above production method. Each structure of a precoat metal plate is as follows.
(Metal plate)
The aluminum alloy plate of thickness 0.5mm and JIS regulation 5052-H34 was used.
(Corrosion resistant coating)
A phosphate chromate film was formed on both sides of the aluminum alloy plate. The adhesion amount of the phosphate chromate film was 20 mg / m ² in terms of Cr.
(Resin film)
A fluorine-based paint in which urethane beads were dispersed was applied to the outermost surface of the phosphoric acid chromate film, and a baking process was performed at a baking temperature (the peak temperature of the metal plate) at 250 ° C. to form a resin film (fluorinated resin matrix layer). .

Here, the following two-component mixed fluorine-based paint was used as the fluorine-based paint. Moreover, the stirring process by a magnet stirrer was used for dispersion | distribution of the urethane bead to a fluorine paint. Furthermore, the average thickness (A) of the fluororesin matrix layer, the average particle diameter (B), (B / A) and the content of the urethane beads used are shown in Table 1.
(Main agent): A fluororesin having a hydroxyl group. The weight average molecular weight is 182,000.
(Curing agent): A blocked isocyanate compound having three isocyanate groups.

(Comparative Examples 1-9)
As a control for Examples 1 to 9, precoated metal sheets of Comparative Examples 1 to 9 were prepared. Comparative Example 1 uses a fluorine-based paint that does not contain urethane beads, and Comparative Examples 2 to 7 have the relationship between the average particle diameter and the average thickness of the fluorine-based resin matrix layer as urethane beads, or the content ratio of the present invention. It was the same as that of Examples 1-9 except having used what does not satisfy the range. Moreover, about the comparative examples 8 and 9, the baking process was performed at the baking temperature which does not satisfy the claim of this invention.

  Next, for the resin films of the precoated metal plates of Examples 1 to 9 and Comparative Examples 1 to 9, the ratio of the fluorine concentration in the outermost surface of the resin film and inside the film is measured, and the crosslinked structure of the fluorine-based resin matrix layer The presence or absence of a urethane bond representing was measured and the results are shown in Table 1. In addition, the measuring method of each characteristic was as follows.

(Percentage of fluorine concentration)
The outermost surface of the resin film and the inside of the film were measured by ESCA (manufactured by Shimadzu Corporation) to obtain atomic% of 5 elements of fluorine, carbon, oxygen, nitrogen and aluminum. These atomic% were converted into mass% using the atomic weight of each element. Of these, only the elements constituting the film, ie, fluorine mass% (F), carbon mass% (C), oxygen mass% (O) and nitrogen mass% (N) are used, and the following formula (1) The ratio of fluorine concentration (A (%)) was calculated.
A (%) = [F / (F + C + O + N)] × 100 (1)

  Here, the outermost surface of the coating refers to the state of the pre-coated metal plate prepared above as it is, that is, the state measured with an argon sputtering time of zero, and the inside of the coating is resin by argon sputtering. It refers to the depth state in which the film is etched in the thickness direction to half the film thickness. Here, ½ of the film thickness is the film depth state in which the argon sputtering time is exactly ½ time until reaching the interface between the resin film and aluminum. As described above, this interface indicates the depth state of the argon sputtering time in which the mass% of Al corresponding to the metal plate is 50% of the total of the five elements measured this time.

  Further, the area of the analysis surface was set to 3 mmφ so that the micro-uniformity of the resin film 3 does not affect the analysis. Needless to say, both the outermost surface of the coating and the inside of the coating were selected and measured at sites not contaminated with oils or the like.

(Urethane bond)
The resin film was measured with FTIR (manufactured by Thermo Nicolay Japan), and the presence or absence of an absorption peak corresponding to the urethane bond was confirmed.

  Next, the anti-sticking property and adhesive peelability of the precoated metal plates of Examples 1 to 9 and Comparative Examples 1 to 9 were measured and evaluated, and the results are shown in Table 1. In addition, the measurement and evaluation methods of the anti-wrinkle property and the adhesive peelability were as follows.

(Prevention of wrinkles on optical disks)
The recording surface of a commercially available optical disk was applied to the surface of the resin film of the precoated metal plate and rubbed 10 times back and forth while gently pressing with a finger, and then the wrinkles on the surface of the optical disk were visually evaluated. At this time, in comparison with the optical disk sample shown in FIGS. 2 to 3, a sample with a close wrinkle state was selected, and the determination of the sample was taken as the determination result of the anti-fouling property of the precoated 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.

(Adhesive peelability)
The adhesive peel strength was measured by a 180 degree peel test specified in JISK6854-2. As the adhesive, a Konica inkjet paper photo label (manufactured by Konica Minolta Holdings, Inc., product number QP10A4GMT) was used. Further, as measurement conditions, a precoated metal plate having a length of 100 mm × width of 60 mm and a label having a length of 100 mm × width of 6 mm were used, and the peeling speed was set to 50 mm / min. In addition, the peeling evaluation in Table 1 was judged as “good” when the adhesive peel strength was 0.1 N / 6 mm or less, and “x” when it exceeded 0.1 N / 6 mm as “bad”.

  From the results shown in Table 1, all of the precoated metal plates of Examples 1 to 9 have an adhesive peel strength of less than 0.1 N / 6 mm, exhibit excellent adhesive peelability, and prevent wrinkles on optical disks. Was also good. Further, as the content of urethane beads increases, the tendency to improve the anti-sticking property is recognized. If the content is 5% by mass or more, it is generally good, and if the content is 10% by mass or more, excellent wrinkles are achieved. The anti-sticking property was shown. Furthermore, in Example 5, since the content of urethane beads was as high as 50% by mass, the viscosity of the fluorine-based paint increased and the paintability was somewhat difficult, but this was not a practically problematic level.

  On the other hand, the precoated metal plates of Comparative Examples 1 and 2 and Comparative Examples 4 to 7 each had an adhesive peel strength of less than 0.1 N / 6 mm, and had excellent adhesive peelability, but the optical disc had wrinkles. The prevention was inferior. Further, Comparative Examples 3, 8, and 9 were all excellent in the anti-flawing property to the optical disc, but the adhesive peel strength exceeded 0.1 N / 6 mm, and the adhesive peelability was inferior. . Further, in Comparative Example 3, the content of urethane beads was 60% by mass, which exceeded the scope of the claims of the present invention, so that the viscosity of the fluorine-based paint was remarkably increased and the paintability was difficult.

  Further, the precoated metal plates of Examples 1 to 9 were pressed into an optical disk drive tray (a part on which a self-made optical disk was placed) and an upper cover of the optical disk drive (a part covering the self-made optical disk). At that time, there was no occurrence of molding defects and the like, and there were no appearance defects such as wrinkles, dirt, oil, etc. on the surface of the produced tray and upper cover.

It is sectional drawing which shows typically the structure of the precoat metal plate which concerns on this invention. FIG. 2 is a photograph of an optical disc sample for determining the anti-sticking property to an optical disk, wherein (a) is a sample with excellent anti-sticking property, and (b) is a sample with good anti-sticking property. FIG. 2 is a photograph of an optical disc sample for determining the anti-sticking property to an optical disk, in which (a) is a sample with slightly poor anti-sticking property and (b) is a sample with poor anti-sticking property. (A) is a perspective view schematically showing a configuration of a self-made disc and a state where a part of an identification label is peeled off, and (b) is a perspective view schematically showing a configuration of an optical disc drive.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Precoat metal plate 2 Metal plate 3 Resin film 4 Fluorine-based resin matrix layer 5 Urethane beads 10 Self-made optical disk 20 Optical disk drive 21 Tray 22 Cover D Disk L Identification label Ln Adhesive part

Claims (7)

A pre-coated metal plate comprising a metal plate and a resin film formed on the surface thereof, the resin film comprising a fluororesin matrix layer and urethane beads dispersed in the fluororesin matrix layer ,
The content of the urethane beads is 5% by mass or more and 50% by mass or less with respect to the fluororesin matrix layer.
The average particle diameter of the urethane beads is 1.1 to 5 times the average thickness of the fluororesin matrix layer,
When the ratio of fluorine concentration on the outermost surface of the resin film is calculated by the following formula (1), the ratio is 15% or more,
A pre-coated metal sheet, characterized in that, when the proportion of fluorine concentration inside the resin coating is calculated by the following formula (1), the proportion is 15% or less.
A (%) = {F / (F + C + O + N)} × 100 (1)
In the formula (1), A is a fluorine concentration ratio, F is fluorine mass%, C is carbon mass%, O is oxygen mass%, and N is nitrogen mass%.   The fluororesin matrix layer of the resin film comprises a fluororesin having at least one of a hydroxyl group, a carboxyl group and an amino group and an isocyanate compound having two or more isocyanate groups, a urethane bond, an acid amide bond and urea. 2. The precoated metal sheet according to claim 1, wherein the precoated metal plates are bonded by at least one kind of chemical bond.   The precoated metal sheet according to claim 1 or 2, wherein an average particle diameter of the urethane beads is 1.5 times or more and 4 times or less of an average thickness of the fluororesin matrix layer.   The precoated metal according to any one of claims 1 to 3, wherein a content of the urethane beads is 10% by mass or more and 40% by mass or less with respect to the fluororesin matrix layer. Board.   The precoated metal plate according to any one of claims 1 to 4, further comprising a corrosion-resistant film between the metal plate and the resin film.   The said metal plate is an aluminum plate or an aluminum alloy plate, The precoat metal plate as described in any one of Claim 1 thru | or 5 characterized by the above-mentioned. In the manufacturing method of the precoat metal plate as described in any one of Claims 1 thru | or 6 provided with a metal plate and the resin film formed in the surface.
A first step of applying a fluorine-based paint in which urethane beads are dispersed on the surface of the metal plate;
And a second step of forming the resin film by baking the fluorine-based paint at 200 ° C. or higher and 280 ° C. or lower.