JP6540825B2 - Coated metal plate - Google Patents

Description

  The present invention relates to a coated metal plate.

  Various lighting fixtures and various video display devices have functions such as brightening the surroundings and projecting an image by emitting visible light. In these devices, a reflection plate is provided around or behind the light source, and the light is reflected by the reflection plate to improve the brightness of the light or to change the traveling direction of the light. In this case, a high visible light reflectance is required on the surface of the reflecting plate in order to suppress the decrease in the amount of light that occurs when light is reflected by the reflecting plate. In order to meet such needs, various metal plates (painted metal plates) on which a white-based coating film having a high reflectance is formed have been conventionally proposed (see, for example, Patent Document 1 and Patent Document 2 below) ).

International Publication No. 2011/034216 JP, 2011-36838, A Unexamined-Japanese-Patent No. 2005-144942 Unexamined-Japanese-Patent No. 1-49629 Unexamined-Japanese-Patent No. 1-153764

  Here, when a coated metal plate having a high reflectance as described above is used particularly for a lighting apparatus or the like, the coated metal plate is often exposed to air. Under the present circumstances, when the dust etc. which exist in the air adhere to the surface of a paint metal plate, although the paint metal plate itself has high reflectance, reflective performance falls by the dust etc. which adhered. It is thought that it will continue. Therefore, it is important how dust and the like are not attached to the surface of the coated metal plate having high reflectance.

  The adhesion of dust and the like to the outermost surface of the coated metal plate is caused by the fact that the dust and the like and the coated metal plate are charged. Therefore, the present inventors considered that it was important to improve the antistatic property of the coating film layer currently formed in the metal plate. Here, the coating film layer having excellent antistatic properties is also a coating film layer having high conductivity. As such a coating layer having high conductivity, a technique for expressing conductivity by widely securing conduction in the depth direction from the surface layer of a coating film to a metal plate as a conductor is widely known. . However, in the coating layer on the metal plate covered with the insulating layer, it was difficult to apply the above-mentioned conductive technology.

  On the other hand, for example, the techniques disclosed in Patent Document 3 to Patent Document 5 can be applied as means for obtaining a coating layer having excellent antistatic properties.

  For example, according to Patent Document 3 described above, the position of the insulating coating on the charge train is lowered (ie, negatively charged) as a means for imparting antistatic properties to the coated metal plate coated with the insulating coating. A method is disclosed which suppresses the adhesion of dust that tends to be negatively charged by facilitating. However, the method disclosed in Patent Document 3 has a problem that it is difficult to exhibit high dust adhesion (that is, excellent antistatic property) because it depends on the chargeability of dust and the like. is there.

  In addition, Patent Document 4 discloses a method of providing an antistatic layer on a metal substrate through an insulating layer, and as the antistatic agent, carbon powder, copper powder, other metal powder, surfactant, A conductive plasticizer etc. are illustrated. However, dark-colored antistatic agents such as metal powder including carbon powder and copper powder have a problem of reducing the reflectance of the highly reflective coating film provided as a base.

  In addition, Patent Document 5 discloses a technology for providing an antistatic (antistatic) coated metal plate capable of being colored in various colors by adding a white conductive whisker to a coating film. However, in Patent Document 5 above, 40 μm to 50 μm is exemplified as the thickness of the coating film to which the whisker is added, and since a large amount of expensive whiskers is used compared to other raw materials, the antistatic metal plate is inexpensive. Have the problem of not being able to

  As described above, in the antistatic techniques as disclosed in Patent Document 3 to Patent Document 5, it has been difficult to easily realize excellent antistatic properties. Further, in consideration of the application of the coated metal plate excellent in antistatic property, such a coated metal plate is preferably excellent in processability.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a method of more simply improving the antistatic property while maintaining excellent processability and reflectance characteristics. It is an object of the present invention to provide a coated metal plate that can be realized by

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention as described in detail below.
The gist of the present invention is as follows.

(1) A film layer comprising one or more layers located above at least one surface of a metal plate, wherein the film layer consisting of one or more layers has an average length of 1 μm to 10 μm, And, at least one antistatic layer having an average thickness of 0.1 μm to 0.5 μm and containing, as an antistatic agent, a needle-like shaped titanium oxide whose surface is coated with a conductive layer having conductivity. The coating layer contains a white paint containing titanium oxide with an average particle diameter of 200 nm to 400 nm, and the content of the antistatic agent in the antistatic layer The coated metal plate having a total light reflectance of 85% or more, and 5% by mass to 30% by mass with respect to the total solid content of the antistatic layer.
(2) The coated metal plate according to (1), wherein the surface resistance of the antistatic layer is 1 × 10 ¹³ Ω or less.
(3) The coated metal plate according to (1) or (2), wherein the thickness of the antistatic layer is 2 μm to 30 μm.
(4) In the antistatic layer, the presence ratio of the long axis of the needle-shaped titanium oxide with respect to the surface normal direction of the metal plate is the same as that of titanium oxide contained in the antistatic layer. The coated metal plate as described in any one of (1)-(3) which is 95% or more of a number.
(5) The coated metal plate according to any one of (1) to (4), further including an insulating layer between the metal plate and the coating layer.
(6) The coated metal plate according to any one of (1) to (5), wherein the antistatic layer is located on the outermost layer of the coated metal plate.
(7) The coating layer is composed of a plurality of layers, and the layer located further on the surface side than the antistatic layer in the coating layer is a layer having conductivity, in (1) to (5) The coated metal plate as described in any one.
(8) The antistatic layer according to any one of (1) to (7), wherein the antistatic layer is composed of a plurality of layers, and the concentration of the antistatic agent is higher as the antistatic layer is located closer to the surface side. Coated metal plate.

  As described above, according to the present invention, it is possible to realize more excellent antistatic properties by a simpler method while maintaining excellent processability and reflectance characteristics.

It is an explanatory view showing typically layer composition of a covering metal board concerning an embodiment of the present invention. It is an explanatory view showing typically layer composition of a covering metal board concerning the embodiment. It is an explanatory view showing typically layer composition of a covering metal board concerning the embodiment. It is explanatory drawing which showed typically the antistatic layer with which the coating metal plate which concerns on the embodiment is provided. It is explanatory drawing for demonstrating the antistatic agent which the antistatic layer which concerns on the same embodiment contains. It is an explanatory view for explaining an antistatic layer concerning the embodiment. It is an explanatory view for explaining an antistatic layer concerning the embodiment. It is an explanatory view for explaining an antistatic layer concerning the embodiment. It is an explanatory view for explaining an antistatic layer concerning the embodiment. It is an explanatory view for explaining an antistatic layer concerning the embodiment.

  The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. In the present specification and the drawings, components having substantially the same functional configuration will be assigned the same reference numerals and redundant description will be omitted.

<On the overall structure of the coated metal plate>
First, the overall structure of a coated metal plate according to an embodiment of the present invention will be briefly described with reference to FIGS. 1A and 2. FIG. 1A and FIG. 2 are explanatory views schematically showing the layer configuration of the coated metal plate according to the present embodiment.

  In the following description, as shown in FIGS. 1A and 1B, the thickness direction of the coated metal plate is referred to as the Z axis direction for convenience, and the width direction of the coated metal plate shown in FIGS. 1A and 1B is the X axis. The direction is the direction, and the depth direction is the Y-axis direction.

  As shown in FIGS. 1A and 1B, the coated metal plate 10 according to the present embodiment includes a metal plate 101 and a coated film layer 103 which is an example of a film layer located above the surface of the metal plate 101. Prepare.

  Here, “above the surface of the metal plate 101” means not only the case where the paint film layer 103 is directly laminated on the metal plate 101 as schematically shown in FIG. 1A but also the schematic manner in FIG. 1B. As shown above, the case where the one or more layers 105 are formed on the metal plate 101 and the paint film layer 103 is formed on the outermost surface of the one or more layers 105 is also included.

  Moreover, although the case where the coating film layer 103 is provided above one side of the metal plate 101 is illustrated in FIG. 1A and FIG. 1B, as schematically shown in FIG. It goes without saying that the paint film layer 103 may be provided on both sides of the above. In addition, although the case where the coating film layer 103 is directly provided on the metal plate 101 is illustrated in FIG. 2, also in this case, as shown to FIG. 1B, the metal plate 101 and the coating film layer 103 are shown. And one or more layers 105 may be present therebetween.

  The metal plate 101 is used as a base material of the coated metal plate according to the present embodiment. The type of the metal plate 101 is not particularly limited, and may be various steel plates, or may be a metal plate made of an alloy containing iron, or non-ferrous metals such as aluminum and titanium. It may be a metal plate. The type of the metal plate 101 may be appropriately selected from the above-described metals in consideration of various properties such as strength and processability required for the coated metal plate 10 according to the present embodiment.

  The coating film layer 103 formed above at least one surface of the metal plate 101 as described above is a layer consisting of one or more layers, and a paint containing a predetermined substance is applied on the metal plate 101, It is formed by drying. In the coated metal plate 10 according to the present embodiment, an antistatic layer containing at least an antistatic agent is formed as one of the coated film layers 103.

  The coated film layer 103 and the antistatic layer will be described in more detail below.

  Further, as schematically shown in FIG. 1B, one or more layers 105 may be formed between the metal plate 101 and the paint film layer 103. The layer 105 is not particularly limited, and any layer may be formed as long as it does not inhibit the function of the coating film layer 103 described later. For example, when the metal plate 101 used as a base material is a metal plate subjected to various surface treatments, the surface treatment layer formed on the surface of the metal plate corresponds to this layer 105.

  In the above, with reference to FIG. 1A and FIG. 2, the entire configuration of the coated metal plate 10 according to the present embodiment has been briefly described.

<About the paint film layer and the antistatic layer>
Subsequently, the coated film layer 103 included in the coated metal plate 10 according to the present embodiment and the antistatic layer included in the coated film layer 103 will be described in detail with reference to FIGS. 3 to 9.
FIG. 3: is explanatory drawing which showed typically the antistatic layer with which the coating metal plate which concerns on this embodiment is provided. FIG. 4 is an explanatory view for explaining an antistatic agent contained in the antistatic layer according to the present embodiment. 5 to 9 are explanatory views for explaining the antistatic layer according to the present embodiment.

[About antistatic layer]
As mentioned earlier, the coating film layer 103 according to the present embodiment is composed of one or more layers, at least one of which is an antistatic layer containing a predetermined antistatic agent. .

  In the following, first, the antistatic layer 111 provided in the paint film layer 103 according to the present embodiment will be described in detail with reference to FIG.

  The antistatic layer 111 according to the present embodiment is a layer in which at least one layer is formed as the paint film layer 103 composed of one or more layers. As schematically shown in FIG. 3, the antistatic layer 111 contains at least titanium oxide 113 having a needle-like shape as an antistatic agent.

  FIG. 4 schematically shows the structure of titanium oxide 113 having a needle-like shape contained in antistatic layer 111 according to the present embodiment. The titanium oxide having a needle-like shape used as the antistatic agent according to the present embodiment has various titanium oxide surfaces, as schematically shown in FIG. 4, for example, in order to make the conductivity higher. It is covered with a conductive layer. The conductive layer covering the surface of titanium oxide is also not particularly limited, and as the conductive layer, for example, known materials such as metal oxides doped with various metals can be used. Hereinafter, needle-shaped titanium oxide whose surface is covered with a conductive layer having conductivity is simply referred to as “needle-shaped titanium oxide”.

  The needle-shaped titanium oxide 113 contained in the antistatic layer 111 according to the present embodiment has an average length (an average length in the long axis direction of the needle-shaped titanium oxide, as shown in FIG. 4). L) is 1 μm to 10 μm, and an average thickness (average length in the direction of minor axis of needle-shaped titanium oxide) D is 0.1 μm to 0.5 μm.

  If the average length L is less than 1 μm, more titanium oxide 113 must be contained to realize the conductivity of the antistatic layer 111 intended in the present embodiment, which is costly It is not preferable from the viewpoint. In addition, when the average length L exceeds 10 μm, the light transmission attenuation rate as described later in the antistatic layer 111 according to the present embodiment is increased, and furthermore, the titanium oxide 113 is precipitated in the paint. This is not preferable because, for example, when coating is performed with a roll coater, the operation stability decreases, for example, the amount of titanium oxide introduced into the coating film fluctuates.

  When the average thickness D is less than 0.1 μm, overlapping of titanium oxides 113 having a needle-like shape can not be sufficiently realized inside the antistatic layer 111, and adhesion of dust or the like can not be realized. It is not preferable because it becomes difficult to efficiently transmit the surface charge that is the cause. When the average thickness D exceeds 0.5 μm, the content ratio of titanium oxide 113 in the thickness direction of the antistatic layer (the thickness in the Z-axis direction shown in FIG. 3) increases to prevent charging. This is not preferable because the layer 111 becomes brittle and the processability decreases.

  In the present embodiment, the more preferable average length L of the titanium oxide 113 is 3 μm to 8 μm, and the more preferable average length L is 5 μm to 6 μm. Further, in the present embodiment, the more preferable average thickness D of the titanium oxide 113 is 0.2 μm to 0.4 μm, and the still more preferable average thickness D is 0.2 μm to 0.3 μm.

  In the antistatic layer 111 according to the present embodiment, the needle-shaped titanium oxide 113 having the above-described shape may be used. However, after the antistatic layer 111 is formed, the titanium oxide 113 as described above may be used. When measuring the average length L and the average thickness D, the measurement may be performed by the following method. That is, a method of measuring the average length L and the average thickness D of the titanium oxide 113 may be used from the observation images of each of the surface and the cross section of the antistatic layer 111. For surface observation of the antistatic layer 111, a scanning electron microscope (SEM) can be used. The cross-sectional observation method of the antistatic layer 111 is not particularly limited, but the coated metal plate 10 is embedded in the normal temperature drying type epoxy resin perpendicularly to the thickness direction of the coating film, and the embedded surface is observed after mechanical polishing. Using a method or Focused Ion Beam (FIB) apparatus, a sample for observation with a thickness of 50 to 100 nm is cut out from the coated metal plate 10 so that the vertical cross section of the coated film can be seen. A method of observing with an electron microscope (Transmission Electron Microscope: TEM) or the like may be used.

  The content of needle-shaped titanium oxide 113 in antistatic layer 111 is 5% by mass to 30% by mass with respect to the total solid content of antistatic layer 111. When the content of the needle-like titanium oxide 113 is less than 5% by mass with respect to the total solid content, the content of the antistatic agent contained in the antistatic layer 111 becomes too small, which is desirable. It is not preferable because it becomes difficult to realize conductivity stably. Further, as the content of the needle-shaped titanium oxide 113 is increased, it is possible to obtain high conductivity. However, when the content of the needle-shaped titanium oxide 113 exceeds 30 mass% with respect to the total solid content, the cost is disadvantageous and the content ratio of the strong titanium oxide 113 is increased. It is not preferable because the processability is reduced. In such a case, the transmission attenuation rate of light as described later may be significantly increased. The content of the needle-shaped titanium oxide 113 is 5% by mass to 30% by mass with respect to the total solid content of the antistatic layer 111, thereby maintaining appropriate processability and appropriate light transmission attenuation rate. It is then possible to realize excellent antistatic properties. The content of the needle-shaped titanium oxide 113 is preferably 10% by mass to 25% by mass, and more preferably 10% by mass to 20% by mass, based on the total solid content.

  In addition to the titanium oxide 113 as the antistatic agent, the antistatic layer 111 according to the present embodiment may contain various binder resins. Such a binder resin is not particularly limited, and various resins widely used in the field of paint of thermoplastic resins and thermosetting resins can be used. As such resin, for example, polyester resin, melamine resin, acrylic resin, isocyanate resin, fluorine resin, epoxy resin, polyamide, polyesteramide, polyvinyl chloride, polyurethane, polycarbonate, polystyrene, polyolefin, and copolymers thereof And mixtures. The binder resin may be a water-based resin or a solvent-based resin.

  The binder resin is preferably at least one resin selected from the group consisting of polyester resins, melamine resins, acrylic resins, isocyanate resins, fluorine resins and epoxy resins, and among them, polyester resins are more preferable.

  The polyester resin preferably has a number average molecular weight of 5,000 to 35,000, and more preferably 10,000 to 30,000. The glass transition temperature (Tg) of the polyester resin is preferably -10 ° C to 70 ° C, and more preferably -5 ° C to 50 ° C.

  Moreover, the said antistatic layer 111 may contain the various additives generally used with respect to a coating film besides the above. As such an additive, various pigments can be mentioned, for example, It is also possible to add various titanium oxides used as a general white pigment. In this case, it is preferable to select titanium oxide used as a pigment so as not to conflict with the various conditions of titanium oxide which functions as the above-mentioned antistatic agent.

  By containing titanium oxide 113 having a specific needle-like shape as described above in the content as described above in antistatic layer 111, titanium oxide 113 having a needle-like shape is schematically shown in FIG. As shown in FIG. 2, they contact each other and exist in the antistatic layer 111. Since the titanium oxide 113 according to the present embodiment has a shape in which the average length L is sufficiently larger than the average thickness D, the short axis of the titanium oxide 113 corresponds to the thickness direction of the antistatic layer 111 (that is, the Z axis direction). And the ratio in which the major axis of the titanium oxide 113 lies is high.

  The thickness (thickness in the Z-axis direction shown in FIG. 3) d of such an antistatic layer 111 is preferably 2 μm to 30 μm. When the thickness d of the antistatic layer 111 is less than 2 μm, the antistatic layer 111 can not exhibit sufficient conductivity, and dust etc. adhere to the outermost surface of the coated metal plate according to the present embodiment. Can be difficult to control. When the thickness d of the antistatic layer 111 exceeds 30 μm, the probability that the major axis of the titanium oxide 113 is parallel to the Z-axis direction increases. In this case, the charge located on the surface in the positive Z-axis direction of the antistatic layer 111 is likely to move in the thickness direction of the antistatic layer 111 along the long axis of the titanium oxide 113, thus causing charging. It may be difficult to achieve conductivity across the entire plane of the prevention layer 111 (the entire XY plane).

  When the thickness d of the antistatic layer 111 is 2 μm to 30 μm, as shown schematically in FIG. 3, the major axis of the needle-shaped titanium oxide 113 is in the surface normal direction of the metal plate (that is, the Z axis). And the ratio in which the major axis of titanium oxide 113 is approximately parallel to the XY plane can be further increased. At this time, sufficient inclination means that the major axis of titanium oxide 113 has an inclination angle of 45 degrees or more, preferably 60 degrees or more with respect to the Z axis (that is, the thickness direction of antistatic layer 111). . As a result, the charge located on the surface in the positive Z-axis direction of the antistatic layer 111 is more likely to move in the horizontal direction in the antistatic layer 111 along the long axis of the titanium oxide 113. It is possible to realize more uniform conductivity over the entire plane (the entire XY plane) of the antistatic layer 111. When the proportion of the titanium oxide 113 whose major axis is inclined to the surface normal direction of the metal plate is 95% or more of the number of titanium oxide 113 contained in the antistatic layer 111, uniform conductivity is obtained. Is easy to obtain. Here, the upper limit value of the presence ratio is not particularly limited, and may be 100%. The thickness d of the antistatic layer 111 is more preferably 3 μm to 25 μm, and still more preferably 5 μm to 20 μm.

  In the antistatic layer 111, the proportion of the titanium oxide 113 in which the major axis of the titanium oxide 113 is inclined with respect to the surface normal direction of the metal plate is the titanium oxide 113 of interest in the cross section with the antistatic layer 111. It can be understood as the existence ratio of The presence ratio is, for example, a microscopic observation of the cross section of the antistatic layer 111 at a magnification of about 1,000, and the number of titanium oxides 113 contained in the field of view, and the number of those whose major axis is inclined, It can be calculated by counting Under the present circumstances, let the thing which averaged the existence ratio in several visual fields (for example, about 10 visual fields) be the existence ratio of the titanium oxide 113 in which the major axis in the antistatic layer 111 inclined with respect to the surface normal direction of a metal plate. Is preferred.

  Here, the thickness d of the antistatic layer 111 may be controlled to an appropriate value by controlling the peripheral speed of each roll, the roll pressure reduction condition, etc., for example, when forming the antistatic layer 111 with a roll coater. It is possible. In addition, when measuring the thickness d of the antistatic layer 111 after the fact, although it is possible to use a known method, for example, the following method can be used. That is, the measurement by cross-sectional observation of the antistatic layer 111 may be used, and the method is not particularly limited, but the above-described method may be used.

  In addition, it is possible to confirm how the titanium oxide 113 having a needle shape exists in the inside of the antistatic layer 111 by, for example, the following method using an electron microscope or the like. . That is, the same method as the method of confirming the average length L and the average thickness D of the titanium oxide 113 may be used.

The surface of the antistatic layer 111 according to this embodiment has a surface resistance (that is, the resistance at the surface in the positive Z-axis direction shown in FIG. 3) measured by a static Honest Meter. The resistance is preferably a value of 1 × 10 ¹³ Ω or less. When the antistatic layer 111 has a surface resistance of 1 × 10 ¹³ Ω or less, the surface charge present on the surface of the antistatic layer 111 can be conducted more efficiently. The lower limit value of the surface resistance is preferably as small as possible, and it is not particularly specified. However, 1 × 10 ⁶ Ω is substantially because there are various difficulties in making it 1 × 10 ⁶ Ω or less. It becomes the lower limit value. The surface resistance of the antistatic layer 111 is more preferably 1 × 10 ⁶ Ω to 1 × 10 ¹⁰ Ω.

  In the antistatic layer 111 according to the present embodiment, the transmission attenuation factor of light with a wavelength of 555 nm is 5% or less. Here, as shown in FIG. 3, the transmission attenuation rate means that light incident on the antistatic layer 111 passes through the antistatic layer 111, and the lower side of the antistatic layer 111 (in the negative Z-axis direction) It shows the ratio of light absorbed by the antistatic layer 111 when it is reflected at the end face of the light source and returned. Here, the human eye can receive light of a wavelength of 380 nm to 780 nm although there is individual difference, and the peak of its sensitivity is around a wavelength of 555 nm. Therefore, when the transmission attenuation rate of light having a wavelength of 555 nm is 5% or less, the human eye feels that the visible light is hardly attenuated when transmitted through the antistatic layer 111. When the antistatic layer 111 according to the present embodiment has the transmission attenuation rate as described above, such a highly reflective coated metal plate as disclosed in, for example, Patent Document 1 and Patent Document 2 can be obtained. Even if it is applied to the above, the high reflectance of the high reflection coated metal plate is not greatly impaired. The transmission attenuation of light having a wavelength of 555 nm is preferably 3% or less.

  In the above, the antistatic layer 111 according to the present embodiment has been described in detail with reference to FIGS. 3 to 4.

[About the paint film layer]
Subsequently, the coated film layer 103 including the antistatic layer 111 as described above will be described in detail with reference to FIGS. 5 to 8.

  As mentioned earlier, the paint film layer 103 according to this embodiment is composed of one or more layers. Therefore, as schematically shown in FIG. 5, the coating film layer 103 may be composed of only the antistatic layer 111. In this case, the antistatic layer 111 according to the present embodiment is positioned immediately above at least one surface of the metal plate 101.

  As described with reference to FIG. 3 and the like, the antistatic layer 111 according to the present embodiment includes titanium oxide 113 having a needle-like shape, and at least a part of titanium oxide 113 has a long axis that is an antistatic layer Lying in the horizontal direction of 111. Therefore, as shown in FIG. 5, when the end of the antistatic layer 111 (for example, at least one end in the X-axis direction) is grounded, the charge present on the surface of the antistatic layer 111 is needle-like. While being conducted by the titanium oxide 113 having a shape, the inside of the antistatic layer 111 is horizontally moved. As a result, the surface charge generated on the surface of the antistatic layer 111 escapes from the end of the antistatic layer 111 in the X-axis direction to the outside. Thereby, in the antistatic layer 111 according to the present embodiment, dust and the like can be prevented from adhering to the surface of the antistatic layer 111, and dust adhesion can be realized.

  Moreover, the coating film layer 103 which concerns on this embodiment may be comprised from several layers. In this case, the antistatic layer 111 according to the present embodiment is preferably located on the outermost layer of the paint film layer 103 as schematically shown in FIG. In this case, the lower layer (layer located in the negative Z-axis direction) 121 of the antistatic layer 111 is not particularly limited.

  Moreover, the case where the coating film layer 103 which concerns on this embodiment is comprised from a several layer, and the antistatic layer 111 does not exist in the outermost layer of the coating film layer 103 is also considered. In this case, as schematically shown in FIG. 8, the upper layer (the layer located on the positive side in the Z-axis direction) 123 of the antistatic layer 111 is preferably a layer having conductivity. By forming the upper layer 123 having such conductivity above the antistatic layer 111, the surface charge generated on the outermost layer of the coating film layer 103 is efficiently conducted to the antistatic layer 111, and the antistatic layer 111 is formed. It can be discharged from the end in the X-axis direction of Needless to say, the insulating layer 107 may be present between the metal plate 101 and the coating film layer 103 also in the case shown in FIG.

  Here, a white paint containing titanium oxide having an average particle diameter of 200 nm to 400 nm is contained in any one or a plurality of layers constituting the paint film layer 103 according to the present embodiment. The layer containing the white paint may be the above-described antistatic layer 111 or a layer other than the antistatic layer 111. A white paint comprising titanium oxide having an average particle diameter of 200 nm to 400 nm in any one or more layers constituting the paint film layer 103, wherein the antistatic layer 111 has the transmission attenuation rate as described above. By being contained, the coated film layer 103 which concerns on this embodiment functions as a highly reflective film layer which has 85% or more of total light reflectance, and the total light reflectance of the coating metal plate 10 which concerns on this embodiment is 85% or more. Here, the total light reflectance as described above is preferably 87.5% or more, more preferably 90% or more. Further, the upper limit value of the total light ray reflectance is not particularly limited, and the higher the value, the better.

  The content of titanium oxide having an average particle diameter of 200 nm to 400 nm can be appropriately selected as necessary, but it is 30% by mass to 60% by mass with respect to the solid content in the contained layer. It is preferable to do. If the content is less than 30% by mass, the total light reflectance of the coated metal plate 10 may be less than 85%. When the content is more than 60% by mass, the processability of the coated metal plate 10 may be reduced. Further, by setting the content of titanium oxide having an average particle diameter of 200 nm to 400 nm to 50% by mass, the total light reflectance is most increased, which is more preferable.

  In addition, as a titanium oxide with an average particle diameter of 200 nm-400 nm, it is possible to use the pigment generally marketed as a white pigment, for example, the titanium oxide "TIPEK" series by Ishihara Sangyo Co., Ltd. series.

  In the above, the coating film layer 103 provided with the antistatic layer 111 was demonstrated in detail, referring FIGS. 5-8.

[Modification of antistatic layer]
Next, a modified example of the antistatic layer 111 according to the present embodiment will be briefly described with reference to FIG.

  Although the example shown in FIG. 3 etc. showed the case where the antistatic layer 111 consists of one layer, the antistatic layer 111 which concerns on this embodiment may be comprised from two or more layers. In this case, as schematically shown in FIG. 9, it is preferable that the concentration of titanium oxide 113, which is an antistatic agent, be higher as the antistatic layer located on the outermost surface side of the coated metal plate 10 be closer. . In the example shown in FIG. 9, the concentration of titanium oxide 113 is higher toward the antistatic layer 111a, and the concentration of titanium oxide 113 is lower toward the antistatic layer 111c. By providing such a concentration gradient of titanium oxide 113, it becomes possible to concentrate titanium oxide 113 in the surface layer, and it becomes possible to express antistaticity more efficiently with a smaller content of titanium oxide 113. .

[Insulating layer]
Although it is the insulating layer 107 which can be provided between the metal plate 101 and the coating film layer 103 as described above, as the insulating layer 107, 90 as disclosed in the above-mentioned Patent Document 1 and Patent Document 2, A highly reflective coating layer having a total light reflectance of% or more may be provided. The high reflection coating film layer as disclosed in Patent Document 1 and Patent Document 2 functions as an insulating layer, and by providing such a high reflection coating film layer as the insulating layer 107, a coated metal plate is provided. It is possible to realize a coated metal plate that reflects light incident on 10 with a high reflectance of 85% or more, and does not cause dust or the like to adhere to the outermost layer.

  Moreover, after forming the high reflection coating film layer which is disclosed by the said patent document 1 or patent document 2 as the insulating layer 107, the coated metal plate 10 in which the coating film layer 103 which concerns on this embodiment was formed is For example, in the 3T bending test at 20 ° C. according to JIS K 5600-5-1 (the standard is a standard corresponding to ISO 1519), excellent processability is realized in which there is no peeling of the film. It becomes possible.

  As the metal plate 101 and the insulating layer 107 according to this embodiment, a high reflection coated metal plate as disclosed in Patent Document 1 or 2 is used as the outermost layer of the high reflection coated metal plate. It goes without saying that the paint film layer 103 according to the present embodiment may be formed.

  Further, when forming a high reflection coating layer as disclosed in Patent Document 1 or 2 as the insulating layer 107 according to the present embodiment, the high reflection coating layer is described prior to the formation. The highly reflective coating layer functioning as the antistatic layer 111 may be realized by further adding titanium oxide 113 having a needle-like shape as described above.

  In the above, the coated metal plate 10 which concerns on this embodiment was demonstrated in detail, referring FIGS. 1-9.

<About the manufacturing method of a covering metal plate>
Next, a method of manufacturing the coated metal plate 10 according to the present embodiment will be briefly described.
The coated metal plate 10 according to the present embodiment is prepared by preparing a predetermined metal plate 101, forming the desired layer 105 on the metal plate 101 as necessary, and then using a paint for forming the antistatic layer 111 as a metal. It is possible to manufacture by apply | coating on the surface of the board 101, and making it dry and solidify.

  Here, the paint for forming the antistatic layer 111 can be prepared according to a known method. That is, water or various organic solvents are prepared as a solvent, and titanium oxide having a needle shape as described above and various binder resins are contained in such solvent to form the antistatic layer 111. It is good if it is a paint for.

  The organic solvent used as the solvent is also not particularly limited, and hydrocarbon organic solvents such as toluene and xylene; ketone organic solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and isophorone; ethyl acetate, acetic acid Ester organic solvents such as butyl and ethylene glycol monoethyl ether acetate; alcohol organic solvents such as methanol and ethanol; ether alcohol organic solvents such as ethylene glycol monoethyl ether and diethylene glycol monobutyl ether; Good.

  In addition, when forming a plurality of layers including the antistatic layer 111 on the metal plate 101, the coated metal plate 10 is formed by repeatedly performing painting, drying, and baking on each of the plurality of layers as commonly performed. Form. However, a coating for forming various layers and a coating for forming the antistatic layer 111 are applied to a part or all of the surface of the metal plate 101 using a multilayer simultaneous application or a wet on wet method. It is preferable from the viewpoint of performance, processability and productivity of each layer to produce by

  Here, in the multilayer simultaneous coating, a plurality of coating liquids can be simultaneously used by an apparatus capable of discharging different coating materials from two or more parallel slits such as a slot die coater or a slide hopper curtain coater. It is a method of applying to a base material in a laminated state, and simultaneously drying and baking this laminated coating liquid.

  Also, with wet-on-wet coating, after a coating liquid is applied on a substrate once, another coating liquid is further applied thereon in a wet state before this coating liquid is dried, and a multilayer of It is a method of drying and baking the coating solution simultaneously. Specifically, as a wet on wet coating method, for example, a coating film layer is coated by a coating method such as a roll coater, dip, curtain flow coater, roller curtain coater, etc., and then this film layer is dried and baked. Before coating, a second layer of paint is applied on top of it by a method that can be applied without contact with a substrate such as a curtain flow coater, roller curtain coater, slide hopper type curtain coater, slot die coater etc. Another method is to dry and bake simultaneously the wet multi-layered coating film.

  In the present embodiment, as a method of simultaneously baking a multilayer simultaneously coated or wet-on-wet coated film, a generally known baking furnace for paint, for example, a hot air drying furnace, a direct fire type heating furnace, an induction heating furnace, infrared rays A heating furnace or a furnace using these in combination can be used.

  In this way, by coating and simultaneously applying the undried coating liquid, the coating liquid of each layer is slightly mixed at the boundary of the coating liquid, thereby controlling the slight unevenness at the interface of each layer. The processability can be made better by enhancing the adhesion of each layer by the anchor effect of the above-mentioned concavo-convex shape. Moreover, since the drying process conventionally performed for each layer is collectively performed, it is advantageous also in terms of productivity and manufacturing cost, and there is also an advantage that the number of drying equipment can be reduced.

  The method of manufacturing the coated metal plate 10 according to the present embodiment has been briefly described above.

  Below, the coated metal plate which concerns on this invention is concretely demonstrated, showing an Example and a comparative example. In addition, the Example shown below is only an example of the coated metal plate which concerns on this invention to the last, and the coated metal plate which concerns on this invention is not limited to the following example.

[Base metal plate]
In order to confirm the performance of the coated metal plate according to the present invention, the following metal plate is used as a base metal plate of the coated metal plate according to the present invention. The types of metal plates used are shown in Table 1 below. In addition, the mild steel plate whose plate | board thickness is 0.5 mm was used for the base material of the metal plate which plated. In addition, the plate thickness of the SUS plate base was 0.5 mm as well. The surface of these metal plates was subjected to an alkaline degreasing treatment, followed by washing with water and drying.

[Chemical conversion treatment layer]
An aqueous solution containing 5 g / l of a silane coupling agent, 1 g / l of water-dispersed silica, and 25 g / l of an aqueous acrylic resin was prepared and used as a chemical conversion treatment agent. Note that γ-glycidoxypropyltrimethoxysilane is used as the silane coupling agent, Snowtex N type manufactured by Nissan Chemical Industries, Ltd. is used as the water-dispersed silica, and polyacrylic acid is used as the water-based acrylic resin. Using. The above-mentioned chemical conversion treatment agent is applied with a roll coater so that the adhesion amount of 100 mg / m ² will be obtained on the surface of the above-mentioned base metal plate, and it is dried under the condition of 60 ° C. reaching the substrate temperature. Formed.

[Undercoat layer]
The coating composition for forming the undercoating layer is prepared by preparing a clear coating of FL641 EU primer manufactured by Nippon Fine Coatings Co., Ltd., which is a commercially available undercoating coating, and using such a coating, aluminum trihydrogen dipolyphosphate (TAICA A mixture of K-WHITE # 105) and calcium ion-exchanged silica (GRACE product SHIELDEX C303) in a ratio of 1: 1 by mass ratio is added 15% by mass with respect to the solid content, and a paint disperser It prepared by stirring. The undercoating paint is applied to the upper layer of the undercoating layer by a roll coater so as to obtain a predetermined dry film thickness, and the metal coating is heated and dried under the condition that the reaching temperature of the metal plate becomes 210 ° C. It was formed.

[Top coat layer]
The coating composition for forming the top coat layer comprises, as a binder resin, an amorphous polyester resin (Toyobo Co., Ltd. product Byron (trade name) 630, number average molecular weight: 23 × 10 ³ , glass transition temperature: 7) C), dissolved in an organic solvent obtained by mixing solvso 150 (trade name) manufactured by ESSO Sekiyu KK (trade name) and cyclohexanone in a mass ratio of 1: 1, as a curing agent melamine resin, completely alkyl type methyl 15% by mass of melamine resin (Cymel (trade name) 303 manufactured by Mitsui Cytec Co., Ltd.) with respect to the solid content of polyester resin, and all catalytic converter 6003 B (trade name) manufactured by Mitsui Cytech Co., Ltd. as a reaction catalyst 0.5 mass% was added with respect to resin solid content, and also the pigment shown in the following Table 2 was added as needed, and it prepared by stirring with the disperser for paints. The top coat is applied to the upper layer of the undercoat film by a roll coater so as to have a predetermined film thickness, and the metal sheet is heated and dried under the condition that the reaching temperature of the metal plate is 230 ° C. to form the top coat film layer 1 I did.

[Pigment]
About the pigment added to the said top coat, the electron micrograph of each pigment was image | photographed, it measured about each sample in the obtained image, and calculated the average value of the measured value obtained. Specifically, the length and thickness of each of about 100 titanium oxides arbitrarily selected from the obtained image are measured, and the average value of the obtained measured values is calculated to obtain the average length. And the average thickness. In addition, as needed, the pigment size was adjusted by classifying the pigment, and the adjusted pigment was used. In Table 2 below, the pigments shown as B3 to B6 and B9 are titanium oxides that function as needle-shaped titanium oxides according to the present invention. B1 is a titanium oxide which does not have a conductive layer, which is used as a general white pigment, and the average particle size thereof is as shown in Table 2 below. B2, B7 to B8 and B10 are titanium oxides used as functional pigments other than the specified in the present invention. Further, B11 is a powder conductive material made of zinc oxide doped with aluminum, and the average particle diameter thereof is as shown in Table 2 below. The average particle sizes of the pigments B1 and B11 shown in Table 2 below are catalog values, respectively. As in Comparative Example 1 to be described later, by incorporating titanium oxide corresponding to B1 in the addition amount shown in Table 3 below, the top coated film layer containing titanium oxide corresponding to B1 is shown in Table 4 below. As shown in the above, it functions as a highly reflective coating layer having a total light reflectance of 90% or more.

In Table 2 below, titanium oxides of FT series and FS series manufactured by Ishihara Sangyo Co., Ltd. and WK-500 series manufactured by Otsuka Chemical Co., Ltd. have needle-like shapes whose surfaces are coated with SnO ₂ doped with Sb. Of titanium oxide.

[1 layer coating layer]
If necessary, the top coat alone is coated with a roll coater to a predetermined film thickness on the upper layer of the base chemical conversion treatment layer, and heat dried under conditions such that the temperature of the metal plate reaches 230 ° C. The coating film layer which consists of one layer of top coat film layer 1 was formed.

[Three-layer coating layer]
In addition, if necessary, the above-mentioned top coat is applied by a roll coater so as to have a predetermined film thickness on the further upper layer of the coated metal plate in which the above-mentioned undercoat and above-mentioned top coat are laminated. It applied and heat-dried on the conditions which reach | attain board temperature of a metal plate to be 230 degreeC, and it formed the coating film layer which consists of an undercoat coating layer, top coat film layer 1, and three layers of top coat film layers. .

  Moreover, among the above three-layer coating layer, two layers of "upper coated film layer 1" and "upper coated film layer 2" are simultaneously applied by a curtain flow coater, and the reaching plate temperature of the metal plate becomes 230 ° C. It heat-dried on conditions, and formed the coating film layer which consists of three layers, an undercoat film layer, "upper coating film layer 1", and "upper coating film layer 2".

[Coating layer thickness]
The prepared coated metal plate was made perpendicular to the thickness direction of the coating layer, embedded in a room temperature drying epoxy resin, and the embedded surface was mechanically polished and then observed by SEM. Subsequently, the thickness of the coating film layer was measured from the cross-sectional image of the obtained coated metal plate.

  In addition, when the state of needle-like titanium oxide contained in the coating film layer was observed together, in all of the produced coated metal plates, the major axis of titanium oxide having a needle-like shape of 95% or more is It was confirmed that it was inclined with respect to the surface normal direction of the metal plate in the state schematically shown in FIG. In addition, the existing ratio of the long axis of the titanium oxide having a needle-like shape inclined to the surface normal direction of the metal plate is calculated according to the above method.

  The coated metal plates produced are summarized in Table 3.

  The following evaluation test was implemented about the coated metal plate shown in Table 3. In addition, also in any test, the said coating film layer coated surface was made into the evaluation surface.

[Surface resistance]
The surface resistance of the coated metal plate produced was measured using a static honest meter (SME-8310, manufactured by Toa Denpa Co., Ltd.). The measured value immediately after applying a voltage of 500 V for 60 seconds to the coated metal plate was used as the surface resistance value, and the surface resistance was evaluated based on the following criteria. In addition, in the following reference | standard, the effect regarding surface resistance is confirmed by evaluation value 3 or more. In addition, regarding the surface resistance, an evaluation value that can obtain an effect more stably is set to 4 or more.

5: Surface resistance value is 1 × 10 ⁹ Ω or less 4: Surface resistance value is 1 × 10 ⁹ Ω or more, 1 × 10 ¹¹ Ω or less 3: Surface resistance value is 1 × 10 ¹¹ Ω or more, 1 × 10 ¹³ Ω or less 2: Surface resistance exceeds 1 × 10 ¹³ Ω, 1 × 10 ¹⁵ Ω or less 1: Surface resistance exceeds 1 × 10 ¹⁵ Ω

[Dust resistance]
The coated metal plate was attached to the wall 30 cm above the back of a copier (ApeosPort C 5540 I made by Fuji Xerox) installed in the office at a 90 ° angle to the ground with the top coat layer grounded. It was stuck and exposed indoors and recovered after 6 months of aging. Next, the reflectance of the coated metal plate before and after exposure was measured in the same manner as the above-described method of measuring the reflectance, and the dust resistance was evaluated based on the following criteria. In the following criteria, an effect on dust adhesion is confirmed with an evaluation value of 2 or more. In addition, regarding dust adhesion, an evaluation value that can obtain an effect more stably is set to 3 or more.

5: The change in reflectance before and after exposure is less than 1.0% 4: The change in reflectance before and after exposure is 1.0% or more, less than 1.5% 3: The change in reflectance before and after exposure is 1.5% or more, 2 .0% or less 2: The reflectance change before and after exposure is 2.0% or more and less than 2.5% 1: The reflectance change before and after exposure is 2.5% or more

[Processability]
The coated metal plate produced was subjected to a 180 ° C. bending test in accordance with JIS K 5600-5-1. In the 180 ° C bending test of the coated metal plate, a state in which any number of coated metal plates are sandwiched at 20 ° C (1T bending for one sheet, 2T bending for two sheets, 3T bending for three sheets, 4 for each) The sheet is subjected to 4T bending, 5 sheets are referred to as 5T bending, and then, a tape is attached to the 180 ° C. bending portion and the peeling of the coating film after forced peeling is observed, and the processability is based on the following criteria Was evaluated. In the following criteria, an evaluation value of 3 or more was regarded as passing.

There is no peeling in the coating at 5: 1 T bending, but there is peeling in the coating at 4: 1 T bending, but no peeling in the coating at 2 T bending. There is peeling in the coating at 3: 2 T bending, In 3T bending, there is no peeling in the coating 2: 3T bending, there is peeling in the coating, but in 4T bending, there is no peeling in the coating 1: 4T bending, there is peeling in the coating

[Reflectance]
Integration of a total light reflectance (hereinafter referred to as "reflectance") of the coated metal plate produced by a spectrophotometer (UV-2600 manufactured by Shimadzu Corporation) using a compacted barium sulfate powder as a reference plate Measured with a sphere. Then, the reflectance was evaluated based on the following criteria. In the following criteria, an evaluation value of 3 or more was regarded as a preferable level for applications where reflectance is desired.

5: reflectance is 90.0% or more and less than 92.5% 4: reflectance is 87.5% or more and less than 90.0% 3: reflectance is 85.0% or more and less than 87.5% 2: Reflectivity is 80.0% or more and less than 85.0% 1: Reflectance is less than 80.0%

  The results of evaluating the produced coated metal plate are summarized in Table 4 below.

  As is clear from the evaluation results summarized in Table 4, the coated metal sheet according to the present invention exhibits excellent surface resistance, adhesion to dust and processability, and titanium oxide known as a general white pigment is used in combination By doing this, a coated metal plate having a reflectance of an evaluation value of 3 or more was obtained. On the other hand, in the coated metal plate used as a comparative example, it did not have excellent surface resistivity, reflectance, and processability.

  Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that those skilled in the art to which the present invention belongs can conceive of various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also fall within the technical scope of the present invention.

DESCRIPTION OF REFERENCE NUMERALS 10 coated metal plate 101 metal plate 103 coated film layer 107 insulating layer 111 antistatic layer 113 needle-shaped titanium oxide

Claims (8)

A coating layer comprising one or more layers located above at least one surface of the metal plate;
The coating layer composed of the one or more layers has an average length of 1 μm to 10 μm and an average thickness of 0.1 μm to 0.5 μm, and the surface is coated with a conductive layer having conductivity. At least one antistatic layer containing a needle-shaped titanium oxide as an antistatic agent,
Any one or more of the coating layers contain a white paint containing titanium oxide having an average particle diameter of 200 nm to 400 nm,
The content of the antistatic agent in the antistatic layer is 5% by mass to 30% by mass with respect to the total solid content of the antistatic layer,
Coated metal sheet having a total light reflectance of 85% or more. The coated metal plate according to claim 1, wherein the surface resistance of the antistatic layer is 1 × 10 ¹³ Ω or less.   The coated metal plate according to claim 1, wherein a thickness of the antistatic layer is 2 μm to 30 μm.   In the antistatic layer, the presence ratio of the major axis of the needle-shaped titanium oxide with respect to the surface normal direction of the metal plate is 95% of the number of titanium oxides contained in the antistatic layer. The coated metal plate in any one of Claims 1-3 which is% or more.   The coated metal plate according to any one of claims 1 to 4, further comprising an insulating layer between the metal plate and the coating layer.   The coated metal plate according to any one of claims 1 to 5, wherein the antistatic layer is located on the outermost layer of the coated metal plate. The coating layer comprises a plurality of layers,
The coated metal plate according to any one of claims 1 to 5, wherein the layer located further on the surface side than the antistatic layer among the coating layers is a layer having conductivity. The antistatic layer comprises a plurality of layers,
The coated metal plate according to any one of claims 1 to 7, wherein the concentration of the antistatic agent is higher as the antistatic layer is located closer to the surface.

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