TW202035140A - Roof material and production method for same - Google Patents

Abstract

The purpose of the present invention is to provide a roof material that: is for overlay roofing that uses coated metal plates that have a coating film that includes a mixture of a fluorine resin and an acrylic resin; and causes less fretting when arranged such that a gap is formed between the roof material and another roof material on which the roof material is laid. The present invention relates to a roof material that comprises coated metal plates that include a metal plate and a coating film that is formed on the surface of the metal plate. During overlay roofing, the roof material can be arranged such that a gap is formed between the roof material and another roof material onto which the roof material is laid. The coating film includes a fluorine resin and a an acrylic resin, the crystallinity of the fluorine resin being 1.3-3.0.

Description

Roof material and manufacturing method thereof

The invention relates to a roofing material and its manufacturing method.

Coated metal sheets are generally excellent in durability, weather resistance, and design, and therefore can be preferably used for roofing materials and the like. In particular, the roofing material requiring long-term durability is preferably a coated metal sheet having a coating film made of fluororesin. As the fluororesin-based coated metal sheet, the following fluororesin-based coated stainless steel sheet is known: a transparent coating film containing a mixed resin of polyvinylidene fluoride and acrylic resin is provided on the surface of the stainless steel sheet, and the transparent The coating film has a specific degree of crystallinity and hardness (for example, refer to Patent Document 1); in addition, the following fluororesin-based coated steel sheets are known: the surface of the steel sheet contains fluororesin, acrylic resin, inorganic sintered pigments, and organic pigments The fluorine-based colored layer of the steel sheet has a coating film made of polyester with a specific glass transition temperature on the back of the steel sheet (for example, refer to Patent Document 2).

In addition, the following method is known: when a metal plate is used as a roofing material for covering, a flange part is formed by folding back the end face of the metal plate and the flange part is used to contact the lower metal plate, so as to move up and down. A gap is formed between the metal plates (for example, refer to Patent Document 3). Patent Document 3 describes that by forming a gap between the upper and lower metal plates by using the flange, it is possible to reduce the risk of corrosion of the metal plate and roof base due to the accumulation of moisture such as rainwater between the metal plates. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2001-009367 [Patent Document 2] Japanese Patent Laid-Open No. 2008-087242 [Patent Document 3] Japanese Patent Laid-Open No. 2016-186212

[The problem to be solved by the invention]

By forming gaps between the upper and lower roofing materials as described in Patent Document 3, corrosion of the metal plates and the like constituting the roofing materials can be suppressed. However, according to research conducted by the inventors, it has been found that the contact portion of the flange portion and the lower roofing material tends to accumulate moisture such as rainwater due to capillary phenomenon or the like, and is more likely to corrode than other portions.

On the other hand, if a metal plate having a coating film containing a mixture of a fluororesin and an acrylic resin described in Patent Document 1 and Patent Document 2 is used as a roofing material, it is expected that the corrosion of the contact portion will also be reduced.

However, in the overlaying construction, it is usually not necessary to fix the vicinity of the contact portion (typically the lowermost part of the upper coated metal plate) with nails or small screws. Therefore, if the roofing material vibrates due to strong wind, or the roofing material expands or contracts due to a temperature change, the flange portion and the surface of the lower roofing material slide finely in the contact portion. Furthermore, the surface (coating film) of the coated metal plate constituting the roof material on the lower side is likely to cause wear (fretting) due to the fine sliding.

In view of the foregoing, the object of the present invention is to provide a roofing material and a method of manufacturing the same. The roofing material is a roofing material for covering using a coated metal plate with a coating film containing a fluorine resin and an acrylic resin Mixtures, and reduce fretting wear when arranged in a way that forms a gap with another roofing material that overlaps. [Means to solve the problem]

One embodiment of the present invention relates to a roofing material, including a coated metal plate, the coated metal plate has a metal plate and a coating film formed on the surface of the metal plate, and can be used in the coating construction. The overlapping roof materials are arranged in such a way that a gap is formed between them. The coating film contains a fluororesin and an acrylic resin, and the degree of crystallinity of the fluororesin is 1.3 or more and 3.0 or less.

Another embodiment of the present invention relates to a method of manufacturing a roofing material, including the step of forming a coating film containing fluororesin and acrylic resin by the following method, the method comprising: forming a fluororesin and acrylic resin on the surface of a metal plate A step of a film of an acrylic resin coating liquid; a step of hardening the film by heating; and a step of cooling the film hardened by heating. In the manufacturing method, the degree of crystallinity of the fluororesin contained in the coating film is adjusted to 1.3 or more and 3.0 or less. [Effects of the invention]

According to the present invention, it is possible to provide a roofing material and a method of manufacturing the same. The roofing material is a covering roofing material using a coated metal plate with a coating film containing a mixture of fluororesin and acrylic resin and reducing The fretting wear when it is arranged to form a gap with another overlapping roofing material.

1. Roofing materials The first embodiment of the present invention relates to a roofing material. The roof material has: a metal plate; and a coating film containing fluororesin and acrylic resin.

1-1. Metal plate The said metal plate can be selected from well-known metal plates in the range which can acquire the effect of this embodiment. Examples of the metal plate include cold rolled steel plate, galvanized steel plate, Zn-Al alloy plated steel plate, Zn-Al-Mg alloy plated steel plate, aluminum plated steel plate, stainless steel steel plate (including Austin iron series, Asada loose iron series, Ferrite system, ferrite and Matian scattered iron two-phase system), aluminum plate, aluminum alloy plate, titanium plate and copper plate.

When the metal plate is a steel plate, the steel plate may be carbon steel containing low carbon steel, medium carbon steel, high carbon steel, etc., or alloy steel containing Mn, Cr, Si, Ni, etc. In addition, the steel plate may be killed steel containing Al killed steel or the like, or may be unquiet steel. When good press formability is required, it is preferably a deep drawing steel sheet containing low-carbon Ti-added steel, low-carbon Nb-added steel, and the like. In addition, a high-strength steel sheet in which the amounts of P, Si, Mn, etc. are adjusted to specific values may also be used. The thickness of the steel plate is not particularly limited, but is preferably in the range of 0.2 mm to 3.0 mm.

The metal plate may also have a plating layer on its surface. The plating layer may be a plating layer formed by a well-known plating process using the metal plate as a base metal plate. The plating may be molten plating or vapor deposition plating. The type of plating is not particularly limited, and Zn plating (Zn plating, Zn-Al plating, Zn-Al-Mg plating, etc.), Al plating, Ni plating, etc. can be used. Among these, Zn plating system and Al plating system are preferable, and Zn plating system is more preferable. The adhesion amount of plating is not particularly limited, but it is preferably in the range of 90 g/m ² to 190 g/m ² .

The metal plate may also have a chemical conversion treatment layer. The chemical conversion treatment layer is arranged between the metal plate and the primer layer in order to improve the adhesion of the primer coating film and the corrosion resistance of the coated metal plate. The chemical conversion treatment layer is a layer formed in contact with the surface of the metal plate, and is composed of a composition adhered to the surface of the metal plate by pre-coating treatment. Examples of the chemical conversion treatment layer include non-chromate-based coatings and chromate-based coatings. All are coatings obtained by anti-rust treatment.

The non-chromate-based coating is preferable from the viewpoint of improving corrosion resistance and reducing the load on the environment in the manufacture and use of coated metal sheets, and the chromate-based coating improves corrosion resistance The view point is better.

Examples of the non-chromate film include Ti-Mo composite film, fluoric acid film, phosphate film, resin film, resin and silane coupling agent film, silicon dioxide film, silicon dioxide and silane coupling Mixture-based film, zirconium-based film, and zirconium and silane coupling agent-based film, etc.

The adhesion amount of the non-chromate-based film can be appropriately determined according to its kind. For example, the adhesion amount of the Ti-Mo composite film is preferably 10 mg/m ² or more and 500 mg/m ² or less in terms of all Ti and Mo, and the adhesion amount of the fluoric acid-based film is preferably fluorine It is 3 mg/m ² or more and 100 mg/m ² or less in terms of conversion or total metal elements, and the adhesion amount of the phosphate film is preferably 0.1 mg/m ² or more and 5 g/m in terms of phosphorus element ² or less, the adhesion amount of the resin-based film is preferably 1 mg/m ² or more and 500 mg/m ² or less in terms of resin conversion, and the adhesion amount of the resin and silane coupling agent-based film is preferably Si Converted to 0.1 mg/m ² or more and 50 mg/m ² or less, the adhesion amount of the silicon dioxide-based film is preferably 0.1 mg/m ² or more and 200 mg/m ² in terms of Si, so The adhesion amount of the silicon dioxide and silane coupling agent film is preferably 0.1 mg/m ² or more and 200 mg/m ² in terms of Si, and the adhesion amount of the zirconium film is preferably calculated in Zr It is 0.1 mg/m ² or more and 100 mg/m ² or less, and the adhesion amount of the zirconium and silane coupling agent film is preferably 0.1 mg/m ² or more and 100 mg/m ² or less in terms of Zr.

Examples of the chromate-based coating include a coating type chromate-treated coating, a phosphoric acid-chromic acid-based treatment chromate antirust treatment coating, and the like. The adhesion amount of these chromate-based films is preferably 20 g/m ² or more and 80 g/m ² or less in terms of chromium element.

The thickness of the metal plate can be appropriately determined based on the use of the coated metal plate and the like. For example, when the coated metal plate is used for exterior building materials, the thickness of the metal plate is preferably 0.2 mm to 3.0 mm, and from the viewpoint of further improving workability, it is preferably 0.25 mm to 2.0 mm.

1-2. Coating The coating film is a resin layer arranged in contact with the surface of the metal plate or via another layer.

The coating film contains a fluororesin and a base resin constituting the film structure of the coating film, and may further contain pigment particles or the like dispersed in the base resin. From the viewpoint of further improving the weather resistance of the coated metal sheet, the coating film is preferably a layer (overcoat coating film) constituting the outermost surface of the coated metal sheet.

The thickness of the coating film is preferably 50 μm or less. The thickness of the coating film can be represented by the average value of the distance from the bottom surface to the surface of a plurality of locations (for example, 10 arbitrarily selected locations) of the coating film. If the thickness is 50 μm or less, there is no need to increase the coating amount of the coating when making the coating film. When the coating film is heated to harden it, blistering (bubble bubbles or pores) is difficult to occur. ) And other coating defects.

In addition, the thickness of the coating film can be appropriately determined based on various factors including the content of the pigment particles, the color tone, and the degree of UV shielding, and the degree of processing during the molding process of the coated metal sheet.

For example, when the content of the pigment particles in the coating film is high, when the hue lightness of the pigment particles (the L value specified in the Japanese Industrial Standards (JIS)) as the color pigment is low, and when the ultraviolet rays of the pigment particles When the degree of occlusion is high, the color rendering property (color concealment property relative to the color of the base) of the coating film by the pigment particles and the ultraviolet shielding rate to the base become high. Therefore, in these cases, the thickness of the coating film can be smaller. In addition, when the degree of processing is low, the ductility required for the coating film becomes low, so the thickness of the coating film can be reduced.

On the other hand, for example, from the viewpoint of maintaining long-term adhesion between the coating film and its substrate (suppressing interfacial fracture for a long time), it is preferable to reduce the ultraviolet transmittance of the coating film, and therefore it is preferable to increase the thickness of the coating film. In addition, when a tensile stress is generally applied to a coating film, even if the tensile displacement is the same, the lower the film thickness, the higher the tensile deformation strain. Therefore, from the viewpoint of reducing the tensile deformation strain, it is also preferable that the thickness of the coating film is large.

As such, the lower limit of the thickness of the coating film cannot be generalized. For example, if the processing degree is equivalent to 4T bending and the L value of the pigment particles as the coloring pigment exceeds 80, the thickness of the coating film is preferably 20 μm or more , More preferably 25 μm or more. In addition, if it is the aforementioned degree of processing and the L value of the pigment particles as the color pigment is 70 or less, the thickness of the coating film is preferably 15 μm or more, and more preferably 18 μm or more.

1-2-1. Fluorine resin The fluororesin is a polyvinylidene fluoride resin. The fluororesin is a resin as a main component of a base resin, and imparts weather resistance, durability, chemical resistance, heat resistance, abrasion resistance, corrosion resistance, stain resistance, and the like to the coating film.

The fluororesin may be one type or more than one type. Examples of the fluorine resin component as the polyvinylidene fluoride resin include polyvinylidene fluoride (PVDF), which is a homopolymer of vinylidene fluoride, and vinylidene fluoride Copolymers with hexafluoropropylene, etc. Among these, the fluororesin is more preferably polyvinylidene fluoride (PVDF). Relative to the total mass of the fluororesin, the content of PVDF is preferably 50% by mass or more, more preferably 70% by mass or more, and more preferably More than 90% by mass. Since PVDF has high weather resistance in particular, it is difficult to increase the surface roughness of a coated metal sheet over time. Therefore, it is possible to suppress the deterioration of the fretting resistance due to the increase in the surface roughness over time, or the progress of corrosion due to the accumulation of rainwater or the like at the location where the surface roughness increases.

The content of the fluororesin in the base resin can be appropriately determined within the range where the effects of this embodiment can be obtained. For example, relative to the total mass of the base resin, it is preferably 50% by mass or more and 85% by mass or less , More preferably 70% by mass or more and 85% by mass or less.

The fluororesin is crystallized at least partially. As the crystal structure of fluororesin, α-type crystals and β-type crystals are known. In this specification, the sum of the crystallinity of the α-type crystal (Icα/Ia) and the crystallinity of the β-crystal (Icβ/Ia) is the crystallinity of the fluororesin.

Specifically, the degree of crystallinity (Icα/Ia) of the α-type crystal is the intensity (Icα) of the α-type crystal (2θ=18.4°) in the wide-angle X-ray diffraction relative to the amorphous halo (2θ=18 °) The value indicated by the ratio of the intensity (Ia). In addition, the degree of crystallinity (Icβ/Ia) of the β-type crystal is the intensity (Icβ) of the β-type crystal (2θ=20.5°) in the wide-angle X-ray diffraction relative to the amorphous halo (2θ=18°) The value indicated by the ratio of the intensity (Ia).

In this embodiment, the degree of crystallinity of the fluororesin is 1.3 or more and 3.0 or less. The fluorine resin has a crystallinity degree of 3.0 or less to make the coating film softer. When the coated metal plates slide against each other, the coating film easily follows the sliding movement, reducing the friction caused by the interface between the coated metal plates Fretting wear. In addition, the fluororesin has a degree of crystallinity of 1.3 or higher without making the coating film too soft. When the coated metal plates are pressed and sliding against each other, the deformation (dentation) of the coating film is suppressed and the coated metal plates are reduced Fretting wear caused by friction at the interface. From the above viewpoint, the degree of crystallinity of the fluororesin is preferably 1.4 or more and 2.8 or less, more preferably 1.5 or more and 2.7 or less.

1-2-2. Acrylic resin The acrylic resin is contained in the base resin from the viewpoint of suppressing excessive crystallization of the fluororesin, the viewpoint of improving the dispersibility of the pigment particles, and the viewpoint of improving the adhesion of the base resin.

The acrylic resin may be one type or more than one type. Examples of the acrylic resin include polymers of acrylic monomers such as methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, and butyl methacrylate, or monomers containing the acrylic monomers的copolymer.

The content of the acrylic resin in the base resin can be appropriately determined within the range where the effects of the present embodiment can be obtained. For example, relative to the total mass of the base resin, it is preferably 15% by mass or more and 50% by mass or less , More preferably 15% by mass or more and 30% by mass or less. In addition, the mass ratio (FR:AR) of fluororesin (FR) to acrylic resin (AR) in the base resin is preferably 50:50 to 85:15. If the content of the acrylic resin is within the above range, the properties of the fluororesin, such as weather resistance, corrosion resistance, and stain resistance, can be fully exhibited. On the other hand, the adhesion of the coating film will not be significantly reduced, so the coating can be maintained. Adequate workability of mounting metal plates.

From the viewpoint of reducing the expansion strain, the acrylic resin is preferably softer. From the viewpoint, the acrylic resin preferably has a glass transition temperature (Tg) of 30° C. or lower. Acrylic resins having a Tg of 30°C or less are difficult to harden during the storage process of the coated metal sheet, and therefore it is possible to suppress the decrease in the workability of the coated metal sheet after long-term storage. From the above viewpoint, the Tg of the acrylic resin is preferably 20°C or less, more preferably 10°C or less. The Tg of the acrylic resin can be a value calculated using the formula of FOX or a value measured by differential thermal analysis (DTA) according to the monomer composition.

In addition, the weight average molecular weight (Mw) of the acrylic resin is preferably 50,000 or more and 200,000 or less, more preferably 70,000 or more and 150,000 or less.

In addition, the acrylic resin is preferably a copolymer of methyl methacrylate and ethyl acrylate. The copolymer is imparted with moderate hardness by methyl methacrylate, and is moderately softened by ethyl acrylate. In addition, the copolymer has improved compatibility with fluororesin by using methyl methacrylate and ethyl acrylate.

1-2-3. Pigment particles The coating film contains pigment particles dispersed in the base resin.

The pigment particles may be colored pigment particles, gloss modifier particles, or extender pigment particles. The pigment particles may be one type or more than one type.

The color pigment particles may be any of organic color pigments and inorganic color pigment particles that are generally available as color pigments for paint. The colored pigment particles are non-transparent and impart a hue to the coating film to form a colored coating film.

Examples of the inorganic color pigments include titanium oxide, chromium oxide, carbon black, iron black, iron oxide yellow, titanium yellow, iron oxide red, Prussian blue, cobalt blue, cerulean blue, ultramarine blue, cobalt green and Molybdenum red, etc.

Examples of the organic coloring pigments include quinacridone red, lithol red B, brilliant scarlet G, pigment scarlet 3B, bright carmine 6B (brilliant carmine 6B), lake red C (lake red C), lake red D, permanent red 4R (permanent red 4R), bordeaux 10B, fast yellow G (fast yellow G), fast yellow 10G, para red, watching red, benzidine yellow, benzidine orange, bon maroon L, maroon M, brilliant fast scarlet scarlet, vermilion red, phthalocyanine blue, phthalocyanine green, fast sky blue, aniline black, etc.

The colored pigment particles may also be particles of a composite oxide fired pigment containing a metal component. The sintered pigment particles include CoAl, CoCrAl, CoCrZnMgAl, CoNiZnTi, CoCrZnTi, NiSbTi, CrSbTi, FeCrZnNi, MnSbTi, FeCr, FeCrNi, FeNi, FeCrNiMn, FeZn, CoCr, MnCo, SnZnTi, etc.

In addition, the colored pigment particles may be metallic pigment particles. Examples of the metallic pigment particles include Al flakes, resin-coated Al flakes, metal oxide-coated Al flakes, Ni flakes, Cu flakes, stainless steel flakes, and the like.

In addition, the colored pigment particles may also be pearl pigment particles. Examples of the pearl pigment particles include titanium oxide coated mica, iron oxide coated mica, and titanium oxide-iron oxide coated mica, and the like.

The number average particle diameter of the colored pigment particles can be appropriately determined within the range where the effects of the present embodiment can be obtained, and is usually 3 μm or less, and preferably 0.01 μm or more and 1.5 μm or less. If the particle size of the colored pigment particles is smaller, the content of the colored pigment particles in the coating film can be increased. From this viewpoint, the number average particle diameter of the colored pigment particles is preferably 2.0 μm or less, more preferably 0.5 μm or less. For example, if the number average particle size is 2.0 μm or less, the coating film can usually contain up to 5% by volume of coloring pigment particles. If the number average particle size is 0.5 μm or less, the coating film Contains up to 20% by volume of colored pigment particles.

The gloss adjuster particles can be used for the purpose of imparting desired gloss to the coating film or for forming irregularities on the upper surface of the coating film. The gloss modifier particles may be one type or more than one type. Examples of the material of the gloss adjuster particles include inorganic materials containing silica and calcium carbonate, and acrylic resins, urethane resins, benzoguanamine resins, styrene resins, polyethylene resins, polypropylene Resin materials such as resin and fluororesin. The number average particle size of the gloss modifier particles contained in the fluororesin layer is preferably 3 μm or less. The average particle size of commercially available gloss modifier particles usually exceeds 3 μm. Therefore, in the case of using commercially available gloss modifier particles, it is better to fractionate particles with a particle diameter of 3 μm or less to use or make the content It is 1% by volume or less.

The content of the gloss modifier particles in the coating film varies, for example, according to the particle size of the gloss modifier particles. However, blending the gloss modifier particles into the coating film brings about the necessary design From an apparent viewpoint, it is preferably 0.2% by volume or more and 1.0% by volume or less.

Alternatively, from the viewpoint of adjusting the gloss in the coating film, the particle size of the gloss adjusting agent particles in the coating film is preferably larger (for example, the number average particle size exceeds 3 μm). When using the gloss modifier particles with a large particle size, the content thereof is preferably 0.2% by volume or more. Furthermore, as described above, from the viewpoint of workability after storage, the content is preferably 1.0% by volume or less.

From the viewpoints of adjusting the hardness of the coating film or reducing the cost of the coating (bulk out effect), the extender pigment particles are pigments contained in the coating film, and generally do not affect the color tone of the coating film. Since extender pigment particles are generally cheaper than fluororesin, the coating film preferably contains extender pigment particles within the range where the effects of the present embodiment can be obtained. In addition, the extender pigment particles preferably have high visible light transmittance. There may be one type of extender pigment particles or more than one type. Examples of extender pigment particles include particles such as barium sulfate, titanium oxide, silicon dioxide, and calcium carbonate. For example, the number average particle diameter of the extender pigment particles is preferably 0.01 μm or more and 1 μm or less. In addition, the content of the extender pigment particles in the coating film is preferably 0.1% by volume or more and 10% by volume or less.

1-3. Other layers The said coated metal plate may have another layer other than the said coating film in the range which can acquire the effect of this embodiment. Examples of the other layers include a chemical conversion treatment layer, an undercoat layer, and an intermediate coat layer. The coated metal plate is preferably laminated with a metal plate, a chemical conversion treatment layer, a primer layer, and the coating film in this order, more preferably a metal plate, a chemical conversion treatment layer, a primer layer, and a middle coating layer are laminated in sequence And the coating film.

1-3-1. Chemical conversion treatment layer The chemical conversion treatment layer is directly arranged on the metal plate for the purpose of improving the adhesion and corrosion resistance of the painted metal plate, that is, between the metal plate and the coating film. The chemical conversion treatment layer is a layer formed in contact with the surface of the metal plate, and is composed of a composition adhered to the surface of the metal plate by pre-coating treatment. Examples of the chemical conversion treatment layer include non-chromate-based coatings and chromate-based coatings. All are coatings obtained by anti-rust treatment.

The non-chromate-based coating is preferable from the viewpoint of improving corrosion resistance and reducing the load on the environment in the manufacture and use of coated metal sheets, and the chromate-based coating improves corrosion resistance The view point is better.

Examples of the non-chromate film include Ti-Mo composite film, fluoric acid film, phosphate film, resin film, resin and silane coupling agent film, silicon dioxide film, silicon dioxide and silane coupling Mixture-based film, zirconium-based film, and zirconium and silane coupling agent-based film, etc.

The adhesion amount of the non-chromate-based film can be appropriately determined according to its kind. For example, the adhesion amount of the Ti-Mo composite film is preferably 10 mg/m ² or more and 500 mg/m ² or less in terms of all Ti and Mo, and the adhesion amount of the fluoric acid-based film is preferably fluorine It is 3 mg/m ² or more and 100 mg/m ² or less in terms of conversion or total metal elements, and the adhesion amount of the phosphate film is preferably 0.1 mg/m ² or more and 5 g/m in terms of phosphorus element ² or less, the adhesion amount of the resin-based film is preferably 1 mg/m ² or more and 500 mg/m ² or less in terms of resin conversion, and the adhesion amount of the resin and silane coupling agent-based film is preferably Si Converted to 0.1 mg/m ² or more and 50 mg/m ² or less, the adhesion amount of the silicon dioxide-based film is preferably 0.1 mg/m ² or more and 200 mg/m ² in terms of Si, so The adhesion amount of the silicon dioxide and silane coupling agent film is preferably 0.1 mg/m ² or more and 200 mg/m ² in terms of Si, and the adhesion amount of the zirconium film is preferably calculated in Zr It is 0.1 mg/m ² or more and 100 mg/m ² or less, and the adhesion amount of the zirconium and silane coupling agent film is preferably 0.1 mg/m ² or more and 100 mg/m ² or less in terms of Zr.

Examples of the chromate-based coating include a coating type chromate-treated coating, a phosphoric acid-chromic acid-based treatment chromate antirust treatment coating, and the like. The adhesion amount of these chromate-based films is preferably 20 g/m ² or more and 80 g/m ² or less in terms of chromium element.

1-3-2. Undercoat From the viewpoint of improving the adhesion and corrosion resistance of the coating film in the painted metal plate, the primer layer is arranged between the metal plate and the coating film. The primer layer is formed on the surface of the metal plate, or when the chemical conversion treatment layer is produced, is formed on the surface of the chemical conversion treatment layer.

The primer layer is made of resin. Examples of the resin include fluororesin, polyester resin, modified silicon resin, acrylic resin, epoxy resin, phenoxy resin, urethane resin, vinyl chloride resin and the like.

The undercoat layer may further contain additives such as anti-rust pigment particles, colored pigment particles, metallic pigment particles, pearl pigment particles, extender pigment particles, and gloss adjuster particles. Examples of the anti-rust pigment particles include particles containing modified silica, vanadate, magnesium hydrogen phosphate, magnesium phosphate, zinc phosphate, aluminum polyphosphate, and other non-chromium anti-rust pigment particles, and particles containing strontium chromate, Particles of chromium-based anticorrosive pigments such as zinc chromate, barium chromate, and calcium chromate.

Examples of the colored pigment particles include titanium oxide, chromium oxide, carbon black, iron black, iron oxide yellow, titanium yellow, iron oxide red, Prussian blue, cobalt blue, sky blue, ultramarine, cobalt green, molybdenum complex red, quine Acridone Red, Lissor Red B, Bright Scarlet G, Pigment Scarlet 3B, Bright Carmine 6B, Lake Red C, Lake Red D, Permanent Red 4R, Claret 10B, Fast Yellow G, Fast Yellow 10G, Right Bit Red, Warchuge Red, Benzidine Yellow, Benzidine Orange, Maroon Red L, Maroon Red M, Bright Fast Scarlet, Vermilion, Phthalocyanine Blue, Phthalocyanine Green, Fast Sky Blue, Aniline Black, CoAl, CoCrAl, CoCrZnMgAl, CoNiZnTi, CoCrZnTi, NiSbTi, CrSbTi, FeCrZnNi, MnSbTi, FeCr, FeCrNi, FeNi, FeCrNiMn, FeZn, CoCr, MnCo and SnZnTi particles.

Examples of the metallic pigment particles include Al flakes, resin-coated Al flakes, metal oxide-coated Al flakes, Ni flakes, Cu flakes, stainless steel flakes, and the like. Examples of the pearl pigment particles include titanium oxide coated mica, iron oxide coated mica, and titanium oxide-iron oxide coated mica, and the like. Examples of the extender pigment particles include particles such as barium sulfate, titanium oxide, silicon dioxide, and calcium carbonate. Examples of the gloss adjuster particles include inorganic materials such as silicon dioxide and calcium carbonate, as well as acrylic resins, urethane resins, benzoguanamine resins, styrene resins, polyethylene resins, polypropylene resins, and fluororesins And other resin materials.

The content of the additive in the primer layer can be appropriately determined within the range in which the effects of the present embodiment can be obtained. For example, by including pearl pigments in the coating film and providing a low-brightness primer layer between the coating film and the metal plate, the pearl pigments can be given a unique hue and brightness. In addition, for example, by adding large-diameter pigment particles with a particle size of about tens of μm to the primer layer, unevenness is formed at the interface between the primer layer and the coating film, which can further improve the adhesion of the coating film. The formation or development of unevenness on the surface of the coated metal plate further improves low gloss. In addition, for example, the content of the anticorrosive pigment in the undercoat layer is preferably 10% by volume or more and 70% by volume or less.

1-3-3. Middle coating From the viewpoint of improving the adhesion and corrosion resistance between layers in the painted metal sheet, the middle coat layer is arranged between the undercoat layer and the coating film.

The middle coating layer is also made of resin. Examples of the resin include fluororesin, polyester resin, modified silicon resin, acrylic resin, epoxy resin, phenoxy resin, urethane resin, and vinyl chloride resin. In the same manner as the undercoat layer, the middle coat layer may further contain the additive as appropriate within the range where the effects of the present embodiment can be obtained. As the additives, for example, the same additives described in the coating film can be used.

Furthermore, in the case of arranging the other layer, the thickness of the coating film may be determined in consideration of the existence of the other layer. For example, when the coated metal plate has a primer layer and a coating film, the thickness of the coating film is preferably 10 μm or more and 35 μm or less from the viewpoint of improving design, corrosion resistance, and processability over time .

1-4. Shape The coated metal plate can be processed into a well-known shape, and considering its use as a roofing material, linear irregularities for drainage may be formed on the surface. In addition, considering that the coated metal plate is used as a roofing material for covering, in order to contact the coated metal plate on the lower side and form a gap between the upper and lower metal plates, it can also be used to form the roof The flange part where the end face of the metal plate that the surface of the material contacts is folded back. Alternatively, for the coated metal plate, in order to be able to perform hemming and seaming fitting, a flange portion that folds back the end surface of the metal plate may be formed. In addition, considering that the coated metal sheet is used as a roofing material for covering, the coated metal sheet on the upper side may be brought into contact to form an embossed portion for holding the coated metal sheet on the upper side.

In the covering construction with these shapes, for the roofing material arranged so as to form a gap with another overlapping roofing material, the contact parts (the concave and convex parts, Flanges, embossed parts, etc.) The roof material vibrates due to strong wind, or when the roof material expands or contracts due to temperature changes, it finely slides with the surface of the lower metal plate. Furthermore, the surface (coating film) of the roofing material on the contact portion or the lower side is likely to cause fretting wear due to the fine sliding.

Furthermore, the coated metal sheet can also be directly processed into the shape of the roofing material, but multiple (for example, two) coated metal sheets can also be used as the surface substrate and the back substrate, which will be the foam core material The resin is sandwiched between them and connected to each other to make a roofing material. The core material can reduce the weight of the roof material and improve the thermal insulation of the roof material.

The foamable resin as the core material may be a urethane resin, a phenol resin, a nurate resin, or the like. Furthermore, when a resin with a large amount of heat such as urethane is used in the core material, the thickness of the surface substrate can be made thin, or the core material can contain inorganic foamed particles, or the roof material can be Non-combustible.

In contrast, with regard to the roofing material of this embodiment, the fluororesin contained in the coating film has a crystallinity of 1.3 or more and 3.0 or less. Therefore, when the roofing materials slide on each other, the coating film is likely to follow the sliding, and it is difficult to cause Fretting wear caused by friction at the interface between roofing materials.

2. Manufacturing method of coated metal plate The coated metal plate can be produced based on a known coating film production method. For example, the coated metal plate can be produced by a method including: forming a film of the coating film (fluororesin coating) on the metal plate, and applying the fluororesin coating to The step of hardening the film to produce the coating film having the characteristics described above regarding the degree of crystallinity.

The preparation of the coating, the coating thereof, and the hardening of the film by the coating can be performed based on a known method.

The paint is a liquid composition containing the materials of the respective layers. The paint is prepared, for example, by dispersing the materials of the respective layers in a solvent. Examples of the solvent include hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, ethers such as cellosolve, and methyl isobutyl ketone, methyl ethyl ketone, isophorone, and cyclohexane. Ketones and other ketones.

The coating may further contain other additives of the solvent. Examples of the additives include hardeners, hardening catalysts, and hydrophilizing agents.

The curing agent crosslinks the base resins when the paint is cured (sintered). The hardening agent can be appropriately selected from known crosslinking agents, hardening agents, and the like according to the type of base resin, sintering conditions, and the like. Examples of hardeners include melamine compounds, isocyanate compounds, and both. Examples of melamine compounds include imino type, methylol imino type, methylol type, or fully alkyl type melamine compounds. The isocyanate compound can be any one of aromatic, aliphatic, and alicyclic, as examples, include m-xylene diisocyanate, hexamethylene diisocyanate, naphthalene diisocyanate, isophorone diisocyanate, and these intercalating Section compound.

The curing catalyst is a component that promotes the curing of the film or the crosslinking of the base resin, and can be appropriately selected from known components having the catalytic action. The content of the hardening catalyst in the paint can be appropriately determined within a range in which sufficient storage stability of the paint can be obtained, and is, for example, 10% by volume to 30% by volume.

The hydrophilizing agent is preferable as an additive to the coating film, and from the viewpoint of preventing rain streak contamination of the coating film, for example, it may be contained in the fluororesin coating in an amount of 30% by volume or less. Examples of the hydrophilizing agent include partial hydrolysis condensates of tetraalkoxysilane.

The coating of the coating material can be performed by known methods such as roll coating, curtain coating, spray coating, and dip coating. The coating amount of the paint is appropriately adjusted according to the required thickness of each layer. In addition, at least the upper layer of the two layers that are directly overlapped by a non-contact coating method such as curtain coating or spraying (a coating method that does not touch the object to be coated and can perform so-called wet-on-wet coating) In the case of application of the paint, the curing of the primer film can be performed simultaneously with the curing of the paint film, so the step of curing the primer film before applying the paint for the upper layer can be omitted.

For example, in the case where the coating film is directly arranged on the other layer, a coating film for the other layer is formed, and then a fluororesin coating film is formed by a non-contact coating method, and then (by heating) The film of the other layer and the fluororesin coating that overlaps it hardens.

The hardening of the coating film can be performed by a known method of sintering the coating onto a metal plate by heating. For example, a metal plate coated with the aforementioned paint such as a fluororesin paint is heated so that its reaching temperature becomes 200°C to 260°C.

Then, the coating film hardened by the fluororesin paint by the heating is cooled at a rate of 200°C/sec or less, preferably 100°C/sec or less, and more preferably 10°C/sec or more from the melting temperature of the fluororesin It is cooled (slowly cooled) at a temperature (200°C) of fluororesin to a temperature (70°C) at which the molecular motion of the fluororesin decreases and crystal growth is difficult, whereby the degree of crystallinity of the fluororesin can be set to 1.3 or more and 3.0 or less.

Alternatively, after the coating film cured by the fluororesin paint by the heating is cooled by a conventional method, the film is heated to recrystallize the fluororesin. By appropriately adjusting the heating temperature and heating time at this time, the crystallinity of the fluororesin can be set to 1.3 or more and 3.0 or less.

The heating temperature can be set to 55°C or higher, preferably 65°C or higher, more preferably 75°C or higher. The higher the heating temperature is, the more the heating time can be shortened, which is better. In addition, although the upper limit of the said heating temperature is not specifically limited, what is necessary is just to be 120 degrees C or less.

The heating time also differs according to the heating temperature, but can be set to 3 seconds or more and 24 hours or less, preferably 1 minute or more and 1 hour or less, more preferably 3 minutes or more and 30 minutes or less . The longer the heating time is, the higher the degree of crystallinity of the fluororesin tends to be, so it is preferably shorter.

Thereby, a coated metal plate having a coating film (overcoat coating film) containing fluororesin and acrylic resin can be obtained. Furthermore, the coated metal plate can be attached to a core material containing foamable resin or the like to form a roofing material. At this time, it is also possible to attach a coated metal sheet with the fluororesin crystallinity adjusted to 1.3 or more and 3.0 or less on the core material containing foamed resin, and then process it into the shape of the roofing material. Unfoamed resin is injected between the coated metal plates, and the resin is foamed and processed into the shape of the roofing material. Furthermore, it is also possible to inject unfoamed resin between the coated metal plates on which the crystallinity of the fluororesin is not adjusted by the heating or the like, and to heat the resin to the above temperature when the resin is foamed In addition, the degree of crystallinity of the fluororesin is 1.3 or more and 3.0 or less.

Furthermore, after the coated metal sheet is processed into the shape of the roofing material, a coating film containing fluororesin and acrylic resin may be formed on the surface of the coated metal sheet, and then by the method such as heating, The degree of crystallinity of the fluororesin is adjusted to be 1.3 or more and 3.0 or less.

The method of manufacturing the coated metal sheet may further include other steps than the above steps within the range where the effects of the present embodiment can be obtained. Examples of the other steps include a chemical conversion treatment step of forming a chemical conversion treatment film, a step of forming an undercoat layer, and a step of forming an intermediate coating layer.

The chemical conversion treatment step can be performed by applying an aqueous chemical conversion treatment solution for forming a chemical conversion treatment film to the metal by a known method such as a roll coating method, a spin coating method, and a spray method. The surface of the plate is dried without washing the metal plate with water after coating. From the viewpoint of productivity, the drying temperature and drying time of the metal plate are preferably 60° C. to 150° C. for 2 seconds to 10 seconds at the reaching temperature of the metal plate, for example.

The step of forming the undercoat layer can be performed by application of a paint for undercoat layer (undercoat paint) and hardening of the film formed thereby. The undercoat paint may optionally contain the solvent and the additives. The primer coating is prepared by uniformly mixing and dispersing the materials. The undercoat paint is applied, for example, by the well-known method described above for the topcoat paint in a coating amount that can obtain a dry film thickness of 1 μm to 10 μm (preferably 3 μm to 7 μm). Metal plate. The coating film of the paint is produced, for example, by heating the metal plate at a temperature of 180° C. to 260° C. due to the reaching temperature of the metal plate and sintering it on the metal plate.

The step of forming the intermediate coat layer may also be performed by applying the intermediate coat paint (medium coat paint) and hardening the film formed thereby in the same manner as the step of forming the undercoat layer. In addition to the material of the middle coat, the middle coat paint may also contain the solvent and the additives as needed. The middle coat paint is also prepared by uniformly mixing and dispersing the materials. The middle coat paint is applied in a coating amount of 3 μm to 20 μm (preferably 5 μm to 15 μm) by the known method described above, for example. The coating layer is produced, for example, by heating the metal plate at a temperature of 180° C. to 260° C. at the reaching temperature of the metal plate and sintering it on the metal plate. [Example]

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited by these examples.

1. Production of coated metal plate 1-1. Base metal plate and its chemical conversion treatment Prepare a 55% Al-Zn alloy steel plate with a hot-dip plating with an adhesion amount of 150 g/m ² on both sides. After alkali degreasing of the plated steel sheet, a non-chromate anti-corrosion treatment solution with a liquid temperature of 20°C is applied to the surface of the plated layer, and dried at 100°C without washing with water to form an adhesion amount in terms of Ti A non-chromate chemical conversion treatment layer of 10 mg/m ² is used to perform anti-rust treatment on the plated steel sheet.

The composition of the non-chromate antirust treatment liquid is as follows. Hexafluorotitanate acid 55 g/L Hexafluorozirconate acid 10 g/L Polyvinylphenol substituted with aminomethyl 72 g/L Water Remaining part

1-2. Formation of primer coating film The surface of the base metal plate after the rust prevention treatment is coated with an epoxy resin primer, and heated so that the plate temperature of the plated steel plate reaches 200°C to form a dry film thickness of 5 μm Base coat coating film.

The composition of the primer coating is as follows. Phosphate mixture 15 vol% Extender pigment 1 (barium sulfate) 5 vol% Extender Pigment 2 (Silica Dioxide) 1 vol% Clear coatings The remaining part

Furthermore, the phosphate mixture is a mixture of magnesium hydrogen phosphate, magnesium phosphate, zinc phosphate, and aluminum tripolyphosphate. In addition, the clear paint is NSC680 manufactured by Nippon Paint Industrial Coatings.

1-3. Formation of top coat film A fluororesin coating is applied to the surface of the base metal plate on which the undercoat coating film is formed, heated so that the plated steel sheet reaches 250°C, and then cooled by any of the following methods to form a dry A top coat coating film with a thickness of 20 μm.

The composition of the top coat paint is as follows. Carbon black 15 vol.% Fluorine resin clear coating Remaining part

Furthermore, the fluororesin clear paint is DICFLOW C manufactured by DIC Co., Ltd., and the paint is 70% by mass of polyvinylidene fluoride and acrylic resin (polyvinylidene fluoride). ): 30% by mass (acrylic resin) mixture. In addition, the acrylic resin is a copolymer in which the mass ratio of methyl methacrylate and ethyl acrylate is 65% by mass (methyl methacrylate): 35% by mass (ethyl acrylate). In addition, the weight average molecular weight and glass transition temperature of the acrylic resin were measured by GPC. As a result, the weight average molecular weight was 140,000 and the glass transition temperature was 50°C.

The cooling method is any of the following. Cooling 1: Let cool (cooling rate is 1℃/sec) Cooling 2: Soak in water at 60°C for water cooling, take it out of the water and wipe the moisture with gauze, then dry in a room at 23°C (cooling rate 150°C/sec). Cooling 3: Soak in water at 20°C for water cooling, take it out from the water, wipe the moisture with gauze, and dry in a room at 23°C (cooling rate: 270°C/sec).

1-4. Processing as roofing material The base metal plate (painted metal plate) on which the top coat coating film is formed is processed into a roofing material by any of the following methods.

1-4-1. No heating (processing method 1) A commercially available foamable resin board is bonded to the coated metal board with an adhesive to make a roofing material. In addition, the coated metal sheets used in these roofing materials are not heated after forming the top coat coating film.

1-4-2. Heating (processing method 2) Heating the coated metal plate changes the degree of crystallinity of the fluororesin contained in the top coat coating film. Then, a commercially available foamable resin sheet is adhered to the coated metal sheet with an adhesive to form a roofing material.

1-4-3. Heating during foaming (processing method 3) Inject a commercially available foamable resin material between two coated metal plates to foam. At this time, the foaming temperature (heating temperature) and time (heating time) are changed to change the crystallinity of the fluororesin contained in the top coat coating film.

2. Evaluation 2-1. Crystallinity of fluororesin Use wide-angle X-ray diffraction to measure the top coat film of the coated metal plate, and set the ratio of the intensity Icα of the α-type crystal (2θ=18.4°) to the intensity Ia of the amorphous halo (2θ=18°) It is the degree of crystallinity (Icα/Ia) of the α-type crystal, and the ratio of the intensity Icβ of the β-type crystal (2θ=20.5°) to the intensity Ia of the amorphous halo (2θ=18°) is set as the β-type crystal The degree of crystallinity (Icβ/Ia). Furthermore, the sum of the crystallinity of the α-type crystal and the crystallinity of the β-type crystal is defined as the crystallinity of the fluororesin possessed by the overcoat coating film.

The measurement conditions of wide-angle X-ray diffraction are as follows. X-ray generator: Rigaku Ultima III Output: 40 kV, 40 mA Monochromator: Graphite Line source: CuKα (0.154184 nm) Scan range: 10°≦2θ≦30° Scanning method: θ-2θ Scanning speed: 0.5°/min

2-2. Resistance to fretting and abrasion A flange part is formed at the end of the painted metal plate, and two painted metal plates are stacked so that the flange part of one of the painted metal plates is in contact with the surface of the other painted metal plate. In this state, the two coated metal plates were set on a vibration tester, and vibrated for 48 hours at an amplitude of 1 mm and a vibration period of 60 Hz in the sliding direction of the flange portion in contact with the surface.

Then, by visually observing the surface of the other coated metal plate in contact with the flange portion, the fretting resistance was evaluated using the following criteria. ◎ No abnormality ○ Slight rubbing marks are observed, but it is no problem × Depression marks or scars are confirmed in the coating film

Tables 1 to 3 show the evaluation results of the degree of crystallinity and fretting resistance when the coated metal plate is produced by changing the presence or absence of heating, the temperature at this time, the heating time, and the cooling method (cooling rate) . In addition, Table 1 shows the roofing materials processed by the processing method 1, Table 2 shows the roofing materials processed by the processing method 2, and Table 3 shows the roofing materials processed by the processing method 3.

[Table 1] distinguish Cooling method (cooling rate) Warm up Evaluation Heating temperature Heating time Crystallinity Resistance to fretting Example Cooling 1 (1℃/sec) - - 2.68 ◎ Example Cooling 2 (150℃/sec) - - 2.01 ◎ Comparative example Cooling 3 (270℃/sec) - - 1.12 X

[Table 2] distinguish Cooling method (cooling rate) Warm up Evaluation Heating temperature Heating time Crystallinity Resistance to fretting Comparative example Cooling 1 (1℃/sec) 80℃ 7th 3.31 X Example Cooling 1 (1℃/sec) 80℃ 5 minutes 2.98 ○ Example Cooling 2 (150℃/sec) 80℃ 5 minutes 2.20 ◎ Example Cooling 3 (270℃/sec) 80℃ 5 minutes 1.62 ◎

[table 3] distinguish Cooling method (cooling rate) Warm up Evaluation Heating temperature Heating time Crystallinity Resistance to fretting Example Cooling 3 (270℃/sec) 80℃ 3 minutes 1.55 ◎ Example Cooling 3 (270℃/sec) 80℃ 2 minutes 1.48 ○ Example Cooling 3 (270℃/sec) 80℃ 1 minute 1.32 ○ Example Cooling 3 (270℃/sec) 70℃ 3 minutes 1.43 ○ Example Cooling 3 (270℃/sec) 70℃ 2 minutes 1.36 ○ Comparative example Cooling 3 (270℃/sec) 70℃ 1 minute 1.27 X Example Cooling 3 (270℃/sec) 60℃ 3 minutes 1.36 ○ Example Cooling 3 (270℃/sec) 60℃ 2 minutes 1.31 ○ Comparative example Cooling 3 (270℃/sec) 60℃ 1 minute 1.20 X Comparative example Cooling 3 (270℃/sec) 50℃ 3 minutes 1.23 X Comparative example Cooling 3 (270℃/sec) 50℃ 2 minutes 1.21 X Comparative example Cooling 3 (270℃/sec) 50℃ 1 minute 1.15 X

From Tables 1 to 3, it is clear that the roofing material (coated metal plate) having a coating film containing a fluororesin and an acrylic resin having a crystallinity degree of 1.3 or more and 3.0 or less has excellent fretting resistance.

In contrast, roofing materials (coated metal sheets) with a degree of crystallinity of less than 1.3 or greater than 3.0 are more prone to wear due to sliding. This application is an application claiming priority based on the Japanese application number 2019-066349 filed on March 29, 2019. The patent scope of the application and the content described in the specification are cited in this application . [Industrial availability]

During the covering construction, the roofing material of the present invention is difficult to generate unique fretting wear when it is arranged to form a gap with another overlapping roofing material. Therefore, the roofing material can be used for a longer period of time.

no

no

Claims (5)

A roofing material includes a painted metal plate, the painted metal plate having a metal plate and a coating film formed on the surface of the metal plate, During the covering construction, the roofing material can be arranged in such a way that a gap is formed between the roofing material and another overlapping roofing material, and The coating film contains fluororesin and acrylic resin, The degree of crystallinity of the fluororesin is 1.3 or more and 3.0 or less. A method for manufacturing a roofing material includes the step of forming a coating film containing fluororesin and acrylic resin by the following method, the method comprising: A step of forming a coating liquid film containing fluororesin and acrylic resin on the surface of the metal plate; The step of hardening the film by heating; and A cooling step of cooling the film hardened by heating, and The degree of crystallinity of the fluororesin contained in the coating film is adjusted to 1.3 or more and 3.0 or less. The method for manufacturing a roofing material according to the second item of the scope of patent application, wherein in the cooling step, the hardened film is cooled at a cooling rate of 200° C./sec or less. The method for manufacturing a roofing material as described in item 2 or item 3 of the scope of the patent application includes a step of heating the hardened film to 55°C or higher after the cooling step. The method of manufacturing a roofing material according to the second or third item of the scope of patent application, wherein after the cooling step, it includes contacting the metal plate on which the coating film is formed with a foamable resin and making the contact The steps of resin foaming, The foaming of the resin proceeds at 55°C or higher.