JP2007275701A - Coating base material and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating base material that is capable of performing molding processing on a base material and has a high reflectance by forming a coating layer exhibiting the high reflectance, and a method for manufacturing the same. <P>SOLUTION: The coating base material having the coating layer including at least a three-layered multilayered structure of a primer layer, an intermediate coat layer, and a top coat layer on at least a part of a surface of the base material, wherein the primer layer contains rutile-type titanium oxide of 20 to 35 vol.%, the intermediate coat layer contains rutile-type titanium oxide of more than 35 vol.% and less than 70 vol.%, and the top coat layer is formed of a coating material having the high reflectance that is the three-layered multilayered structure or more containing rutile-type titanium oxide of 0 to 35 vol.%, and the method for manufacturing the same. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coated substrate having a high diffuse reflectance and a method for producing the same.

  Lighting equipment, AV equipment, electronic equipment, mobile equipment, liquid crystal televisions, plasma displays, etc. have functions such as brightening the surroundings, transmitting optical signals, or projecting optical images by emitting visible light. . Some of these devices are provided with a reflecting plate and reflect light to the reflecting plate to improve the luminance of light or change the direction of light. For this reason, in order to avoid a decrease in the amount of light when light is reflected on the reflecting plate, a high visible light reflectance is required on the reflecting plate surface. Conventionally, as means for increasing the reflectivity of the reflector surface, metal has been polished into a mirror surface, or a white paint with high reflectivity has been applied. In addition, in the catalog “View Coat (registered trademark)” of Nippon Steel Corp., a pre-coated steel plate for a reflector for a lighting fixture in which a white paint is applied in advance is also disclosed.

  Further, for example, in Patent Document 1, a metal thin film layer and a resin layer containing inorganic fine particles are sequentially laminated on one surface of a base film, and the metal thin film layer is made of aluminum, and a resin layer containing inorganic fine particles. The technology of an excellent light reflecting film as a reflector of a liquid crystal display device is disclosed by setting the refractive index nf of the inorganic fine particles constituting the refractive index and the refractive index nb of the resin constituting the same layer to nf−nb ≧ 0.4 Has been. Furthermore, for example, Patent Document 2 discloses an undercoat layer having a film thickness of 50 to 100 μm containing 150 to 300 parts by mass of rutile titanium oxide with respect to 100 parts by mass of resin on an aluminum plate for a back panel of a liquid crystal display. A back panel of a liquid crystal display in which 100 to 250 parts by mass of rutile-type titanium oxide is contained in the undercoat layer with respect to 100 parts by mass of the resin, and an overcoat layer having a gloss of 15 or less and a film thickness of 10 to 30 μm is formed. Techniques for highly diffuse reflective coated metal plates for use in the art are disclosed.

JP-A-10-730 JP 2002-172735 A

  By the way, in recent years, reflectors used in electrical appliances such as reflectors for lighting fixtures and liquid crystal displays have a complicated structure and design of electrical appliances. Accordingly, there is a need for the reflectors to be molded and processed into various shapes. Is growing. However, when a film is used as the substrate as in the technique described in Patent Document 1, a film in which a thin metal film layer or a resin layer containing inorganic fine particles is previously laminated is formed into a desired shape. However, it is necessary to laminate a thin metal film layer or a resin layer containing inorganic fine particles after the film is formed into a desired shape in advance. However, when the shape of the reflecting plate is complicated, it is difficult to laminate the film with a uniform film thickness in the processed part. On the other hand, in the technique described in Patent Document 2, the undercoating layer and the overcoating layer can be preliminarily applied on the aluminum plate and then molded. However, in a general pre-coating line, the coating can be performed once. It is very difficult to coat the undercoat layer (50 to 100 μm) with a film thickness, and there are disadvantages such as low productivity because two or more overcoats are required.

  Therefore, in view of the structure and design of electrical products, the reflector must be molded and used, and considering the productivity of the reflector, the reflection described in Patent Document 1, Patent Document 2, etc. It is difficult to use a plate, and it has been necessary to use a conventional pre-coated steel plate for a reflector for a luminaire that has been previously coated with a white paint.

  Therefore, in view of the above situation, the present invention provides a coated base material having a high diffuse reflectance and a method for producing the same by forming a coating layer that can be molded on the base material and exhibits a high diffuse reflectance. It is intended to provide.

As a result of intensive studies to solve the above-mentioned problems, the present inventors formed three or more coating layers on the base material, and each layer compensated for diffuse reflectance and molding processability, thereby achieving high diffusion. The present inventors have found that both reflectance and moldability can be achieved, and have completed the present invention based on such knowledge. That is, the gist of the present invention is as follows.
(1) A coated substrate having a coating layer having a multilayer structure of at least three layers of a primer layer, an intermediate coating layer, and a top coating layer on at least a part of the substrate surface, wherein the primer layer is a rutile type oxidation 20 to 35 vol% of titanium, the intermediate coating layer contains rutile type titanium oxide more than 35 vol% and less than 70 vol%, and the overcoat layer contains 0 to 35 vol% rutile type titanium oxide, Among them, the coated base material characterized in that the thickness of the intermediate coating layer is the thickest.
(2) The coated base material according to (1), wherein a main resin of the primer layer is a fluororesin.
(3) The coated base material according to (1), wherein the main resin of the overcoat layer is a fluororesin.
(4) The coated substrate according to (1), wherein the entire coating layer has a thickness of less than 100 μm.
(5) The minimum value of diffuse reflectance of light in the wavelength region of 450 nm to 750 nm (is the minimum value of diffuse reflectance and the definition and measurement method of diffuse reflectance described) described above is 92.5% or more, and The coated substrate according to (1), wherein the diffuse reflectance of light having a wavelength of 555 nm is 95% or more.
(6) The coated substrate according to (1), wherein the substrate is a metal plate.
(7) A primer layer coating containing 20 to 35 vol% rutile titanium oxide in the coating solid content, in order from the substrate side, on at least a part of the substrate surface, and a rutile titanium oxide in the coating solid content. Coating, characterized in that a coating for an intermediate coating layer containing more than 35 vol% and less than 70 vol% and a coating for an upper coating layer containing 0 to 35 vol% rutile titanium oxide in the solid content of the coating is applied and baked. A method for producing a substrate.
(8) The method for producing a coated base material according to (7), wherein the top coating layer coating and the intermediate coating layer coating are simultaneously baked.
(9) An electronic device using the coated substrate according to any one of (1) to (6).

  According to the present invention, it has become possible to provide a material capable of ensuring high diffuse reflectance and workability, which has been difficult to achieve in the past by manufacturing by continuous coating line. As a result, high diffuse reflectance has been required so far, and a white film with high diffuse reflectance was created and the reflector, which was mainly used in the two steps of pasting it, was applied continuously. It is now possible to manufacture in a single process, where the paint is directly applied to the substrate in the line, and the process can be omitted. Therefore, it can be said that the present invention is an extremely industrial invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  In the present invention, three or more coating layers are formed on the base material, and each layer succeeds in achieving both high diffuse reflectance and moldability by supplementing the diffuse reflectance and molding processability.

  In the present invention, rutile type titanium oxide is used as a pigment. This is because the refractive index of rutile titanium oxide is higher than that of other pigments, and the difference in refractive index from the resin used as the binder can be increased, so that the reflectance at the interface between the pigment and the resin can be increased. .

  Here, the primer layer indicates a layer closest to the base material. However, even for the layer closest to the base material, the layer with a thickness of less than 1 μm for the purpose of improving the adhesion between the base material and the coating film and improving the corrosion resistance is not considered as a primer layer. The upper layer is a primer layer.

  The overcoat layer indicates a layer exposed on the surface farthest from the substrate.

  In the case of a three-layer structure, the intermediate coating layer corresponds to a portion sandwiched between and in contact with the primer layer and the top coating layer. However, in a coating layer having a multilayer structure of four or more layers, the intermediate coating layer and the primer layer are separated from each other. All layers with a rutile-type titanium oxide concentration of more than 35 vol% and less than 70 vol% disposed between them are regarded as intermediate coating layers. If the total thickness is greater than the thickness of the other layers, a high diffuse reflectance is obtained. Easy to get. Further, even when the concentration of rutile type titanium oxide continuously changes and the boundary between the respective layers is unclear, the entire range where the concentration of rutile type titanium oxide is more than 35 vol% and less than 70 vol% is defined as an intermediate coating layer.

  Concerning the rutile titanium oxide concentration in the primer layer, the primer layer hides the base material and exhibits high diffuse reflectance, and at the same time, ensures the adhesion between the base material to be coated and the coating layer. Is needed. If the rutile-type titanium oxide concentration is too high, the coating film becomes brittle and it is difficult to ensure adhesion, so it is better not to raise the rutile-type titanium oxide concentration extremely for the primer layer. The hiding power of the coating film shows good hiding properties when the concentration of rutile titanium oxide is increased as the concentration of rutile type titanium oxide is increased. However, when the concentration exceeds 35 vol%, the workability decreases, so the primer layer The rutile type titanium oxide concentration needs to be 20 to 35 vol%. In order to obtain a higher level of hiding power, the rutile type titanium oxide concentration should be 25 vol% or more. Since it is preferable that the titanium oxide concentration be 30 vol% or less, it is preferable to set the rutile titanium oxide concentration to 25 to 30 vol% in order to achieve both workability, adhesion and concealability at a higher level.

  Regarding the concentration of rutile-type titanium oxide in the intermediate coating layer, the intermediate coating layer is required to have concealability and high diffuse reflectance, but not as flexible as the primer layer. Therefore, since the rutile type titanium oxide concentration can be made higher than that of the primer layer, the rutile type titanium oxide concentration in the intermediate coating layer is over 35 vol%, and when a higher diffuse reflectance is required, it is 40 vol% or more. preferable. However, when the volume concentration of rutile type titanium oxide is 70 vol% or more, the intermediate coating layer itself becomes brittle, so that the rutile type titanium oxide concentration of the intermediate coating layer is less than 70 vol%. In particular, in the case of a coated base material that requires processability, it is preferable that the concentration of the rutile type titanium oxide is less than 60 vol% because the flexibility of the coating layer can be ensured. When the concentration of titanium oxide is less than 57 vol%, it is preferable because higher workability can be secured.

  Regarding the rutile-type titanium oxide concentration in the topcoat layer, it is better that the topcoat layer has a high diffuse reflectance, but the most important role of the topcoat layer is to protect the entire coating layer. Therefore, a coating film that is too brittle is not preferable. In addition, when the concentration of rutile titanium oxide increases, the amount of rutile titanium oxide exposed on the coating film surface increases. When a metal touches such a coating, the metal is worn by rutile titanium oxide, and black marks are left on the coating surface. Such a black mark is not preferable for the coated base material of the present invention whose main purpose is to exhibit a high diffuse reflectance. Therefore, the upper limit of the rutile-type titanium oxide concentration in the overcoat layer is preferably the same as that of the primer layer, and the lower limit is not limited, and is 0 to 35 vol% including the case where no rutile-type titanium oxide is contained. However, it is more preferable that the rutile type titanium oxide concentration is 20 to 30 vol% if not only protection of the entire coating layer but also high diffuse reflectance is required for the overcoat layer and both are desired to be compatible at a high level.

  The volume concentration of rutile titanium oxide can be measured as follows. First, scrape only the layer for measurement. From the scraped area A1 and depth D1, the volume V1 of the coating film is obtained as V1 = A1 × D1. Next, the shaved coating is heated at 500 ° C. for 1 hour to decompose the binder component. The remaining part can be considered as rutile titanium oxide. The volume Vt1 of the rutile titanium oxide may be measured by a method such as immersion in a liquid, but the mass Mt1 is measured, and the density of a general rutile titanium oxide pigment is about 3800 to 4200 kg · m−3. Therefore, the density of the rutile type titanium oxide pigment may be determined as 4000 kg · m−3 and the volume as Vt1 = Mt1 ÷ 4000 kg · m−3. From the volume V1 of the coating film thus obtained and the volume Vt1 of the rutile type titanium oxide, the volume concentration Ct1 of the rutile type titanium oxide can be obtained as Ct1 = Vt1 ÷ V1 × 100 (vol%).

  The other is to cut the coated substrate at a plane perpendicular to the coated surface and check the thickness T2 of the coated layer from the cross section with an optical microscope or an electron microscope. After measuring with a micrometer, the coating layer is peeled off, and the thickness at the same place is measured again with a micrometer, and the thickness T2 of the coating layer is determined from the difference. Next, the coating layer is peeled by an arbitrary area A2. The peeled coating layer is heated in a crucible at 500 ° C. for 1 hour. The mass Mt2 of titanium oxide contained in the remaining ash is determined. Since the general density of rutile-type titanium oxide pigment is about 4000 kg · m−3, the volume V2 of the coating layer is V2 = A2 × T2, and the volume Vt2 of the rutile-type titanium oxide is Vt2 = Mt2 ÷ 4000 kg · m−. 3 can be calculated. From the volume of the coating layer thus obtained and the volume of the rutile type titanium oxide, the volume concentration Ct2 of the average rutile type titanium oxide in the whole coating layer can be obtained as Ct2 = V2 ÷ V2 × 100 (vol%). Next, the element distribution in the film thickness direction of the coating layer is confirmed by GDS (glow discharge emission spectroscopy), EMPA (electron beam microanalyzer) or the like of the coating layer cross section. From the element distribution and the average rutile-type titanium oxide volume concentration obtained in advance, the rutile-type titanium oxide volume concentration in each depth and each layer can be obtained.

  The mass ratio of the organic component and the inorganic component by thermal decomposition of the organic component may be confirmed by TG (thermogravimetric analysis).

  Since the coated base material having a high diffuse reflectance of the present invention is mainly intended to reflect visible light, it is important that the diffuse reflectance in the wavelength region where the sensitivity of the human eye is high is high. It is. The human eye can sense light with a wavelength of 380 to 780 nm, although there are individual differences, and the peak of the sensitivity is in the vicinity of 555 nm. Therefore, it is necessary to strongly reflect light having a wavelength centered at 555 nm.

  The average particle size of rutile-type titanium oxide used as a pigment is that the smaller the particle size in the same volume, the larger the surface area and the wider the reflective interface, so the diffuse reflectance becomes higher, but the particle size of the pigment is larger. If it becomes too small, light of a long wavelength is transmitted. Therefore, in order to make the reflection interface as wide as possible and reflect visible light strongly, the average particle size of rutile titanium oxide is preferably 200 to 400 nm, more preferably 250 to 350 nm. The average particle size of the rutile type titanium oxide here is 20% from the smallest particle size among the rutile type titanium oxides observed in the field of view by observing the part to be confirmed at 10,000 times with an electron microscope. And the arithmetic average value of the particle sizes of the remaining rutile titanium oxide excluding 5% from the larger one. In addition, rutile type titanium oxide, silica, alumina, zirconia, zinc oxide, antimony oxide, organic substances (eg, polyol organic substances such as pentaerythritol and trimethylolpropane, organic acid salts of triethanolamine and trimethylolamine, etc.) An alkanolamine-based organic material, a silicon-based organic material such as a silicon resin or alkylchlorosilane), or the like may be used. Specifically, the “Taipek (registered trademark)” series manufactured by Ishihara Sangyo Co., Ltd., the “TATM” series manufactured by Fuji Titanium, the “TITANIX (registered trademark)” series manufactured by Teika, and the like can be used. Any rutile type titanium oxide in the present invention may be used.

  The primer layer has a role of concealing the base material and ensuring adhesion of the coating layer to the base material. Since increasing the rutile titanium oxide concentration makes it difficult to ensure adhesion, it is necessary to demonstrate higher concealment within the rutile titanium oxide concentration range where adhesion can be secured. For the binder main resin, it is better to select a binder that can show higher diffuse reflectance in combination with rutile titanium oxide. It is known that when the refractive index difference between the pigment and the binder resin is large, the reflectance at the pigment-binder resin interface becomes high, and a high diffuse reflectance can be obtained. Since it is low, when a pigment having a high refractive index such as rutile type titanium oxide and a fluororesin are combined, the refractive index difference between the pigment and the binder becomes large, and a high diffuse reflectance can be obtained. Therefore, it is preferable to select a fluororesin as the binder resin for the primer layer. Moreover, in order to ensure the adhesiveness of a base material and an intermediate coating layer, it is still more preferable to contain an epoxy resin. The fluororesins are not particularly limited, but polyfluoroethylene-based polytetrafluoroethylene, polytrifluoroethylene, polydifluoroethylene, polyhexafluoropropylene, and poly (fluoroalkyl) vinyl ether structures are molecular chains. Any material may be used as long as it is contained therein, and it may be a copolymer of these structures, vinyl ether, vinyl ester, or the like, or a blend of acrylic resin. Specifically, "Lumiflon (registered trademark)" manufactured by Asahi Glass Co., Ltd., "Duflon (registered trademark)" manufactured by Nippon Paint Co., Ltd., "Dionin TM" manufactured by 3M Company, "Fluonate (registered trademark)" manufactured by Dainippon Ink & Chemicals, Inc. , “Zeffle (registered trademark)” manufactured by Daikin Co., Ltd., “Zaflon (registered trademark)” manufactured by Toagosei Co., Ltd., and the like can be used. In the case of a vinylidene fluoride homopolymer, it is generally mixed with an acrylic resin. These resins may be crosslinked with a generally known crosslinking agent such as isocyanate or melamine resin as required. Isocyanates are also commercially available, such as “Sumijoule (registered trademark)”, “Desmodule (registered trademark)” series manufactured by Sumika Bayer, and “Takenate (registered trademark)” series manufactured by Mitsui Takeda Chemical Co., Ltd. Can be used. Melamine resins are also commercially available, for example, “Cymel (registered trademark)” manufactured by Mitsui Cytec, “My Coat (registered trademark)” series, “Beccamin (registered trademark)” manufactured by Dainippon Ink and Chemicals, The “Super Becamine (registered trademark)” series and the like can be used. In the present invention, the main resin refers to a component having a mass ratio of 50% or more among components serving as a binder of the coating layer. Whether these resins are the main component can be confirmed by combining infrared spectroscopy, nuclear magnetic resonance spectrum, mass spectrometry and the like.

  Since the intermediate coating layer is a layer for obtaining the diffuse reflectance which is the greatest object of the present invention, it is the thickest of the coating layers and has a high concentration of rutile titanium oxide. In order to obtain a high diffuse reflectance, a fluororesin may be used as the main resin in the same manner as the primer layer. However, the intermediate coating layer is protected by being sandwiched between the top coating layer and the primer layer, so that the single layer may become brittle. A rutile type titanium oxide concentration may be used. Therefore, even if the main resin is not necessarily a fluororesin, a high diffuse reflectance can be achieved. Also, if you want to ensure the coating strength when the concentration of rutile titanium oxide is increased, it is difficult to change the structure because the fluororesin is chemically stable, and it is easy to adjust the physical properties of the resin. However, since the cost is often higher than other resins, polyester resin or acrylic resin, or a mixture of these, which is easier to adjust the physical properties of the resin than fluororesin, is advantageous in terms of cost. Is good.

  The topcoat layer is a layer intended to protect the coating layer, and it is important for the diffuse reflectance that the diffuse reflectance secured by the primer layer and the intermediate coat layer is not adversely affected. Therefore, the film thickness may be thinner than the primer layer and the intermediate coating layer, and the rutile type titanium oxide concentration needs to be determined on the assumption that the coating film strength can be obtained. As for the main resin, it is not always necessary to select a fluororesin that can provide a high diffuse reflectance, and a resin that can easily ensure the coating strength may be selected. A polyester resin, an acrylic resin, or a mixture thereof may be used. Just choose. However, when high diffuse reflectance and long-term stability are required, it is preferable to use fluororesin as the main resin. When the coating material of the present invention is used continuously for a long time in a reflector application, the resin may be deteriorated by light and the diffuse reflectance may be lowered. In this case, since the fluororesin is chemically stable, deterioration due to light can be suppressed. As a fluororesin, the thing similar to what was used for the primer layer can be used.

  Further, a matting agent such as silica may be added to the topcoat layer as necessary in order to enhance the light diffusibility.

  The film thickness of each layer is not particularly limited except that the intermediate coating layer is the thickest, but it is necessary to increase the film thickness to achieve high diffuse reflectance, and it is necessary to reduce the film thickness in terms of workability and economy. Therefore, it is sufficient to make the balance.

  If the primer layer is too thin, high concealability is difficult to obtain, and it is difficult to relieve the stress applied to the intermediate coating when processed. Therefore, the lower limit is about 3 μm, and if possible, it should be 5 μm or more. . The upper limit is not particularly limited as long as it does not cause a problem in manufacturing, but since a thicker layer is laminated on top of this, even if it is made too thick and the concealability is increased, the effect in the final product is diminished. 、 Effects that are worth the cost cannot be obtained. Therefore, the upper limit is 50 μm or less, and usually up to about 35 μm.

  The thickness of the intermediate coating layer is preferably thicker than the other layers because this layer exhibits the maximum effect of the present invention, and in order to achieve a high diffuse reflectance, the thickness should be 15 μm. If possible, it should be at least 20 μm. The upper limit is not particularly limited as long as it does not cause a problem in manufacturing, but if the film thickness exceeds a certain level, the rate of increase in diffuse reflectance slows down, and an effect commensurate with the cost of increasing the film thickness is obtained. I can't. Therefore, the upper limit is 80 μm or less, and it is about 50 μm for ease of manufacturing.

  The thickness of the overcoat layer must be too thick because the main purpose of forming this layer is not to increase the diffuse reflectance, which is the main purpose of the present invention, but to protect the entire coating layer and to reduce gloss. There is no. From the viewpoint of protection, if it can be uniformly coated, a film thickness of 0.1 μm or more can play a role, but in order to exhibit a stable effect, 1.0 μm or more is more preferable. The upper limit is not particularly limited as long as the diffuse reflectivity of the overcoat layer is the same level as the other layers, but it is a film that does not adversely affect even if the diffuse reflectivity is inferior to the other layers. The thickness is preferably 20 μm or less, and usually 10 μm or less. However, if the overcoat layer is a layer that contains almost no pigment and the main purpose is to protect the surface and improve the light diffusibility by reducing the gloss, the thickness of 5 μm or less is better for the diffuse reflectance. Less adverse effect and more preferable.

  The total thickness of the coating layer is not particularly limited, but there is a concern that workability will deteriorate if it is too thick, and when the coating layer is formed by applying and baking a continuous coating baking line paint, Since boiling easily occurs, it is preferable that high diffuse reflectance can be achieved with a film thickness of less than 100 μm. Moreover, it may be said that it is not economical if it is too thick, and it is more preferable if a high diffuse reflectance can be achieved with a film thickness of less than 80 μm.

  On the other hand, a material having a minimum value of diffuse reflectance of light in the wavelength region of 450 nm to 750 nm being 92.5% or more and a diffuse reflectance of light having a wavelength of 555 nm being 95% or more is used as a reflector of a lighting fixture. High illuminance can be obtained. In particular, when it is used as a reflector of a liquid crystal display, if only the diffuse reflectance of 555 nm is high, the brightness of the screen can be obtained, but it becomes difficult to produce saturation. Therefore, if the minimum value of the diffuse reflectance of light in the wavelength region of 450 nm to 750 nm with such a film thickness is 92.5% or more and the diffuse reflectance of light having a wavelength of 555 nm can be 95% or more, the reflection material It is also excellent in productivity, economy and reflection characteristics.

  The base material of the coated base material of the present invention is not particularly limited, but a metal plate is suitable because it can be easily processed and formed after the coating layer is formed on the base material. Any of the metal plates is not particularly limited, and examples thereof include steel plates, stainless steel plates, aluminum plates, zinc plates, copper plates, and alloy plates thereof, and further, metal plated on these metal plates. Is mentioned. Among these, examples of plating treatment on steel sheets include hot dip galvanized steel sheets, electrogalvanized steel sheets, galvannealed steel sheets, aluminum plated steel sheets, aluminum-zinc alloy plated steel sheets, zinc-aluminum-magnesium alloy plated steel sheets, zinc -Various plated steel sheets such as aluminum-magnesium-silicon alloy-plated steel sheet, zinc-magnesium alloy-plated steel sheet, tin-plated steel sheet, lead-plated steel sheet, and chromium-plated steel sheet. In addition, these metal plates can be subjected to chemical conversion treatment. For the chemical conversion treatment, generally known chemical conversion treatments such as coating chromate treatment, electrolytic chromate treatment, zinc phosphate treatment, and a chromate-free treatment which does not contain hexavalent chromium which has been developed recently can be used.

  The method for producing a coated base material having a high diffuse reflectance according to the present invention is not particularly limited, but at least a part of the surface of the base material, in order from the base material side, in the solid content of the composition in the rutile. Type titanium oxide containing 20-35 vol%, other than 80% by mass of the solid content is a resin component, and an organic solvent is added to the primer layer as necessary, rutile in the solid content of the composition The solid content of the coating composition for the intermediate coating layer in which the organic solvent is added to the resin composition containing more than 35 vol% and less than 70 vol% of the type titanium oxide, and 80% by mass or more of the other solid content as a resin component. By applying and baking a paint for topcoat layer containing 0 to 35 vol% of rutile type titanium oxide in which 80% by mass or more of the other solids is a resin component and adding an organic solvent as required Preferred method Arbitrariness. If the coating layer is formed by painting in this way, when the coating layer is produced separately as a film, multiple steps such as film creation and application to the substrate are required, whereas the coating layer is formed on the substrate. There is an advantage that the coating layer can be formed directly and the number of processes can be reduced. The coating method is not particularly limited, and roll coating, roller curtain coating, curtain flow coating, air spray coating, brush coating coating, die coater coating, dip coating, ink jet coating, etc. The usual method is mentioned.

  Each layer may be laminated by applying the respective paints for each layer, baking and curing, and may be laminated at the same time before curing, or a combination of both methods. For example, if the intermediate coating layer and the top coating layer are baked at the same time, the baking process may be performed once for the primer layer and once for the intermediate coating layer and the top coating layer. If you want to bake separately, you have to install three equipment for the baking process that takes a relatively long space on the continuous coating line, or if you have only two baking processes you have to pass the line twice On the other hand, if baking is performed at the same time, if two baking apparatuses are installed, it is only necessary to pass through the line once, so that productivity can be improved. The method of laminating in the uncured paint state is not particularly limited, but there are two major methods. One is a method of applying each layer separately, and one is a method of applying a plurality of layers simultaneously. When each layer is applied separately, the lower layer may be coated by the normal method described above, but the upper layer is preferably coated by a method that does not apply a large impact to the uncured lower layer. . If you paint with a method that gives a big impact to the lower layer, the upper and lower layers will mix. The upper layer coating method is not particularly limited as long as it does not disturb the lower layer violently, but roller curtain coating, curtain flow coating, air spray coating, die coater coating, dip coating, Examples include inkjet coating. When multiple layers are applied simultaneously, each layer must not be mixed during application. Although it does not specifically limit as a coating method, Methods, such as multilayer slide curtain coating, are mentioned. It is preferable that the multilayers formed by such a method are baked at the same time because the adhesion between the layers baked at the same time becomes high.

  In the electrical and electronic equipment using the coated base material according to the present invention, the coated base material has a high diffuse reflectance in the visible light region. Therefore, the same light source is brighter than before, and the light source Even if the number is reduced or the input power is reduced, the same brightness as before can be secured. There are no particular limitations on the electrical and electronic equipment that can make use of these characteristics, and examples include lighting equipment, electrical decoration, AV equipment, mobile equipment, and various displays. It is preferably used for a plate, an illumination reflector, a reflector in an interior signboard, and the like.

  The invention will be further described on the basis of examples.

First, the evaluation method will be described.
1) Diffuse reflectance measurement A spectrophotometer “UV265” manufactured by Shimadzu Corporation was used with an integrating sphere reflection accessory attached, and a barium sulfate powder pressed and used as a reference plate. In the evaluation, with respect to the diffuse reflectance at 555 nm, which is the wavelength with the highest sensitivity of human eyes, 95% or more was achieved as a reference, 95% or more was achieved, and less than 95% was not achieved. For diffuse reflectance of 450 nm to 750 nm, 92.5% is the standard, and the minimum value of diffuse reflectance in that wavelength range is 92.5% or more, but less than 92.5% is not achieved It was.
2) Illuminance measurement of luminaires Fig. 1 shows an outline of an experimental apparatus used for illuminance measurement of luminaires in the examples. A commercially available fluorescent lamp luminaire (2) was mounted in a wooden box (1), and a commercially available illuminometer sensor (4) was installed 30 cm away from the fluorescent lamp (3) to measure the illuminance. . The reflector (5) is a reflector made of pre-coated steel plate for lighting fixture reflectors coated with white paint introduced in the catalog “View Coat (registered trademark)” of Nippon Steel Corporation The illuminance of the reflection plate was measured, and the illuminance when the reflection plate produced using the coated substrate produced was measured. And, from the illuminance when measured with the existing reflector and the illuminance when measured with the reflector of the produced coated substrate, the illuminance change rate = ([illuminance on the reflector with the produced coated substrate] − [existing Illuminance on the reflector of the light source)) × 100 / [illuminance on the existing reflector], when the illuminance change rate is 15% or more: ◯, when the illuminance change rate is 5% or more and less than 15%: Δ , When the illuminance change rate was less than 5%: evaluated as x. In this experiment, a fluorescent lamp with a 16-type lamp output of 16 W was used.
3) Workability It tested by the method of the bending resistance which is one of the testing methods regarding the resistance of the coating film standardized by JISK5400. A mandrel having a diameter of 3 mm was used, and the coating layer was bent outward (side not in contact with the mandrel). The evaluation was visually confirmed for cracks.
4) Metal contamination resistance Tested by a DuPont method of impact resistance, which is one of the test methods relating to the resistance of the coating film specified in JIS K 5400. The fall height of the weight was 150 mm, the size of the shooting mold and the cradle was a radius of 6.35 mm, the weight of the weight was 500 g, and the weight was dropped toward the shooting mold. In the evaluation, the presence or absence of discoloration in the impact part was confirmed visually.

  Next, the test material will be explained.

  As the base material of the coated base material, a galvanized steel sheet subjected to chromate treatment was used. The coating layer was formed by applying, baking, and curing a coating of each layer.

  Fluorine resin, acrylic resin, and polyester resin were used for the binder of the coating layer. As the fluororesin, “Lumiflon (registered trademark) LF552” manufactured by Asahi Glass Co., Ltd., which is a commercially available ethylene trifluoride resin, was used. For the crosslinking agent, “Sumidur (registered trademark) BL3175” manufactured by Sumika Bayer Urethane Co., Ltd., which is a blocked isocyanate based on commercially available HDI (hexamethylene diisocyanate), is mixed in an equivalent amount of OH / NCO = 1: 1. Furthermore, a fluorine-based clear paint was obtained by adding 0.05% by mass of the reaction catalyst “TK-1” manufactured by Mitsui Takeda Chemical Co. to the resin solid mass. As the acrylic resin, “Alloset (registered trademark) 5535” manufactured by Nippon Shokubai Chemical Industry Co., Ltd., which is a commercially available acrylic resin, was used. For the cross-linking agent, “Desmodur (registered trademark) BL3175” manufactured by Sumitomo Bayer Urethane Co., Ltd., which is an oxime block of an isocyanurate body of hexamethylene diisocyanate, is mixed in an equivalent amount of OH / NCO = 1: 1, and a curing catalyst. As a result, an acrylic clear paint was obtained by adding 0.025% by mass of dibutyltin dilaurate to the resin solid mass. As the polyester resin, “Byron (registered trademark) GK140” manufactured by Toyobo Co., Ltd., which is a commercially available organic solvent soluble type / amorphous polyester resin, is mixed with an organic solvent (Solvesso 150 and cyclohexanone in a mass ratio of 1: 1. Used) was used. As the cross-linking agent, 15 parts by mass of “Cymel (registered trademark) 303” manufactured by Mitsui Cytec Co., Ltd., which is a commercially available hexa-methoxy-methylated melamine, is added based on 100 parts by mass of the polyester resin solid content. A polyester-based clear paint was obtained by adding 0.5 parts by mass of “Catalyst (registered trademark) 6003B” manufactured by Mitsui Cytec Co., Ltd., which is an acidic catalyst.

The rutile type titanium oxide has an average particle size of 0.28 μm (280 nm) and a density of 4.0 g · cm ⁻³ manufactured by Ishihara Sangyo Co., Ltd. “Taipec (registered trademark) CR-95”, average particle size of 0.21 μm (280 nm). manufactured by Ishihara Sangyo Kaisha, Ltd. of density 4.2 g · ^{cm -3} "TIPAQUE (R) CR-63", average particle size 0.30 .mu.m (300 nm), manufactured by Tayca Corporation density 4.1 g · ^{cm -3} 'TITANIX ( (Registered trademark) JR-301 was used.

Example 1
In Example 1, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that the paint can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Example 2)
In Example 2, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that the paint can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the acrylic resin clear paint solid content, and the paint is prepared until the viscosity becomes a paintable viscosity. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Example 3)
In Example 3, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that the paint can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide having an average particle size of 0.28 μm is mixed with 45 vol% of the fluororesin clear paint solid content, and the paint is prepared until the viscosity reaches a level at which it can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

Example 4
In Example 4, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that the paint can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a topcoat layer, a paint is prepared by mixing 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm with 70 vol% of the acrylic resin clear paint solid content until the viscosity becomes a paintable viscosity. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Example 5)
In Example 5, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that the paint can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that the paint can be applied. The base material was coated with a blade coater so that the film thickness after baking and curing would be 3 μm, with the addition of a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1. I baked it.

(Example 6)
In Example 6, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and the paint is prepared. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, a paint obtained by adding a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 until a viscosity capable of coating the fluororesin clear is added, and the film thickness after baking and curing becomes 5 μm. In this way, the substrate was coated with a blade coater and baked at a maximum plate temperature of 230 ° C.

(Example 7)
In Example 7, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that the paint can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. A paint obtained by adding a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 is applied to the substrate with a blade coater so that the film thickness after baking and curing is 40 μm. In addition, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and the paint is prepared. A paint containing a mixture of cyclohexanone and a mass ratio of 1: 1 is blended so that the film thickness after baking is 5 μm Painted substrate with coater and simultaneously baked two layers at peak metal temperature of 230 ° C..

(Example 8)
In Example 8, as a primer layer, 70 vol% of the fluororesin clear paint solid content was mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and the paint was prepared until the viscosity became coatable. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. A paint obtained by adding a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 is applied to the substrate with a blade coater so that the film thickness after baking and curing is 40 μm. In addition, as a top coat layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and a paint is prepared. Blade coating is applied so that the film thickness after baking and curing is 5 μm after adding paint mixed with cyclohexanone at a mass ratio of 1: 1. Painted substrates in chromatography, were simultaneously baked two layers at peak metal temperature of 230 ° C..

Example 9
In Example 9, 20 vol% of rutile titanium oxide having an average particle diameter of 0.28 μm was mixed with 80 vol% of the solid content of the fluororesin clear paint as a primer layer, and the paint was prepared until the viscosity became paintable. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Example 10)
In Example 10, as a primer layer, 35 vol% of rutile-type titanium oxide having an average particle size of 0.28 μm is mixed with 65 vol% of the solid content of the fluororesin clear paint, and the paint is prepared. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Example 11)
In Example 11, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and the paint is prepared until the viscosity becomes coatable. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, blending 36 vol% of rutile titanium oxide with an average particle size of 0.28 μm with 64 vol% of the polyester resin clear paint solid content, the paint is prepared, and until the viscosity can be applied Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Example 12)
In Example 12, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle diameter of 0.28 μm, and the paint is prepared until the viscosity becomes a paintable viscosity. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, blending 69 vol% of rutile titanium oxide with an average particle size of 0.28 μm to 31 vol% of the polyester resin clear paint solid content, until the viscosity becomes paintable Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Example 13)
In Example 13, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that the paint can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, a paint is prepared by mixing 35 vol% of rutile titanium oxide having an average particle size of 0.28 μm with 65 vol% of the solid content of the polyester resin clear paint, and until the viscosity becomes coatable. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Example 14)
In Example 14, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and the paint is prepared until the viscosity becomes a paintable viscosity. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.21 μm is mixed with 45 vol% of the polyester resin clear paint solid content, and the paint is prepared until the viscosity reaches a level at which it can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Example 15)
In Example 15, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and the paint is prepared. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.30 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity reaches a level at which it can be applied. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Comparative Example 1)
In Comparative Example 1, as a primer layer, 45 vol% of fluororesin clear paint solid content is mixed with 55 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and the paint is prepared until the viscosity becomes coatable. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 55 vol% of rutile titanium oxide with an average particle size of 0.28 μm is mixed with 45 vol% of the solid content of the polyester resin clear paint, and the paint is prepared until the viscosity becomes paintable. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Comparative Example 2)
In Comparative Example 2, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle diameter of 0.28 μm, and the paint is prepared until the viscosity becomes coatable. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. On top of that, as an intermediate coating layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and the paint is prepared until the viscosity becomes coatable. Paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 40 μm, and the maximum plate temperature reached 210 ° C. I baked it. Furthermore, as a top coat layer, 70 vol% of the polyester resin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm until the viscosity becomes such that it can be applied. A paint with a mixture of Solvesso 150 and cyclohexanone mixed at a mass ratio of 1: 1 was applied to the substrate with a blade coater so that the film thickness after baking and curing was 5 μm. I baked it.

(Comparative Example 3)
In Comparative Example 3, as a primer layer, 70 vol% of the fluororesin clear paint solid content is mixed with 30 vol% of rutile titanium oxide having an average particle size of 0.28 μm, and the paint is prepared until the viscosity becomes paintable. Paint with a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 was applied to the substrate with a bar coat so that the film thickness after baking and curing was 25 μm, and the maximum temperature reached 210 ° C. I baked it. In addition, 55 vol% of rutile titanium oxide having an average particle size of 0.28 μm is mixed with 45 vol% of the polyester resin clear paint solid content as an overcoat layer (corresponding to the intermediate coat layer in the examples of the present invention). Prepare a paint and add a mixture of Solvesso 150 and cyclohexanone in a mass ratio of 1: 1 until the viscosity can be applied, and use a bar coat so that the film thickness after baking is 40 μm. The material was painted and baked at a maximum plate temperature of 230 ° C.

  Table 1 shows the results of evaluating the diffuse reflectance, adhesion, and metal contamination resistance of each Example and Comparative Example.

  Examples 1 to 15 were good results in all evaluations of diffuse reflectance, workability, and metal contamination resistance. In Comparative Example 1 in which the content of the rutile titanium oxide in the primer layer was excessive from the range of the present invention, the diffuse reflectance and metal contamination resistance were good, but cracks occurred in the processed part. In Comparative Example 2 in which the content of rutile titanium oxide in the intermediate coating layer was less than the range of the present invention, the workability and the metal contamination resistance were good, but a high diffuse reflectance was not obtained. In Comparative Example 3 having no overcoat layer according to the present invention, although the diffuse reflectance was good, metal contamination was observed.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

It is a schematic diagram of the illumination intensity measuring apparatus used in each Example and comparative example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wooden box 2 Lighting fixture 3 Fluorescent lamp 4 Illuminance meter 5 Reflector

Claims (9)

A coated substrate having a coating layer composed of a multilayer structure of at least three layers of a primer layer, an intermediate coating layer, and a top coating layer on at least a part of the substrate surface,
The primer layer contains rutile titanium oxide in an amount of 20 to 35 vol%, the intermediate coating layer contains rutile titanium oxide in an amount of more than 35 vol% and less than 70 vol%, and the overcoat layer contains rutile titanium oxide in an amount of 0 to 35 vol%. %, And the thickness of the intermediate coating layer is the thickest among the coating layers.   The coated substrate according to claim 1, wherein the main resin of the primer layer is a fluororesin.   2. The coated substrate according to claim 1, wherein the main resin of the overcoat layer is a fluororesin.   2. The coated substrate according to claim 1, wherein the entire coating layer has a thickness of less than 100 [mu] m.   The minimum value of diffuse reflectance of light in a wavelength region of 450 nm to 750 nm is 92.5% or more, and the diffuse reflectance of light having a wavelength of 555 nm is 95% or more. Coated substrate.   The coated substrate according to claim 1, wherein the substrate is a metal plate.   A primer layer coating containing 20 to 35 vol% of rutile titanium oxide in the coating solid content and 35 vol% of rutile titanium oxide in the coating solid content in order from at least a part of the substrate surface. A coated base material characterized by coating and baking a coating for an intermediate coating layer containing less than 70 vol% and a coating for a top coating layer containing 0 to 35 vol% rutile-type titanium oxide in the solid content of the coating. Production method.   The method for producing a coated base material according to claim 7, wherein the top coating layer coating and the intermediate coating layer coating are baked simultaneously. The electronic device using the coating base material in any one of Claims 1-6.

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