Fluoroplastic coated metal plate

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a fluororesin-coated metal plate having a design surface, and more specifically, the coating layer has excellent adhesion even when processed or used in a harsh environment, and has excellent corrosion resistance over a long period of time. The present invention relates to a fluororesin-coated metal plate that can maintain its design and can be suitably used for various interior and exterior building material applications, kitchen-related applications, and electrical and electronic-related applications.

【0002】

[Conventional technology]

A resin layer for protecting the design surface and imparting corrosion resistance is provided on the surface of the metal plate conventionally used for decorative plates, exterior plates, etc., especially on the surface of the metal plate having a design such as coloring or printing. Has been done. This resin layer is required to have various properties depending on the application, in addition to transparency to the extent that the design is not impaired. For example, when a metal plate is used in a kitchen or the like, heat resistance and nonflammability are required. Scratch resistance, stain resistance, etc. are required, and when used as a building exterior material such as a roofing material or a wall material, weather resistance is also required. By the way, if the resin layer is formed of a fluororesin having excellent properties such as corrosion resistance, stain resistance, heat resistance, non-adhesiveness, nonflammability, chemical resistance, and weather resistance, the above requirements can be met at once. Can be met.

【0003】

However, there is a problem that fluororesin is inferior in adhesiveness. Therefore, when the design surface of the metal plate is coated with the fluororesin, the fluororesin layer film is usually attached to the design surface of the metal plate with an adhesive, that is, the coating layer is generally a colored resin on the surface of the metal plate. It has a structure of a layer (design layer) / adhesive layer / fluororesin layer. For example, JP-A-7-60899, JP-A-7-299884, JP-A-7-304131, JP-A-9-123349, JP-A-10-123349, JP-A-8-174757, etc. Discloses a fluororesin-coated metal plate having such a layer structure.

【0004】

In the fluororesin-coated metal plate as described above, the metal surface is subjected to a chemical conversion treatment, a primer layer is provided between the metal plate and the colored resin layer, and the adhesive surface of the fluororesin layer is surface-treated. It is also known that the adhesiveness (adhesion) is enhanced. Further, for example, in JP-A-7-60899, a specific adhesive is used in order to obtain a fluororesin-coated laminated steel plate having excellent adhesion and discoloration resistance, and ethylene-tetrafluoroethylene is used as the fluororesin. It has also been proposed to use copolymers (ETFE).

【0005】

However, although the adhesiveness of the conventional fluororesin-coated metal plate is improved by the above-mentioned various methods, it cannot be said that it is sufficient. For example, a decorative plate around a kitchen range, an outer wall exposed to direct sunlight, a roofing material, etc. If it is used in a harsh environment, or if it is subjected to molding processing such as bending, the interface between the colored resin layer and the metal surface may peel off or the colored resin layer may crack, and further, fluoropolymer may occur. The resin layer may peel off and rust may occur.

【0006】

[Problems to be Solved by the Invention]

The present invention has been made in view of the above-mentioned prior art, has excellent adhesion between a metal plate and a coating layer, particularly a colored resin layer, and is used for a long period of time under harsh conditions or subjected to molding processing. However, it is an object of the present invention to provide a fluororesin-coated metal plate that is less likely to cause problems such as peeling between the metal and the coating layer, deterioration of appearance due to cracks in the colored resin layer, and generation of rust.

【0007】

[Means for solving problems]

The present inventor diligently studied a fluororesin-coated metal plate having a colored resin layer and a fluororesin layer. As a result, peeling and cracking of the colored resin layer caused residual stress and shrinkage force on the colored resin layer due to the coating of the fluororesin layer. It was presumed that this was due to the action, and it was found that when coating the fluororesin, it was necessary to limit the thickness of the colored resin layer, which had not been considered in the prior art. The present invention has been found that the above-mentioned problems such as peeling and cracking can be solved by making the thickness of the colored resin layer less than 10 μm and at the same time forming the fluororesin layer with a perfluoro-type fluororesin. It came to be completed.

【0008】

That is, the fluororesin-coated metal plate according to the present invention is provided on at least one surface 1a of the metal plate 1 via a colored resin layer 2 and a transparent adhesive layer 3 on the surface of the colored resin layer 2. It is characterized in that it has a fluororesin layer 4, the thickness of the colored resin layer 2 is less than 10 μm, and the fluororesin layer 4 is made of a perfluorotype fluororesin.

【0009】

The fluororesin-coated metal plate may have a primer layer 5 between the metal plate 1 and the colored resin layer 2. Further, the colored resin layer 2 and / or the fluororesin layer 4 may have a printing layer 6 on a surface in contact with the adhesive layer 3.

【0010】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the fluororesin-coated metal plate according to the present invention will be specifically described. FIG. 1 shows a partial cross-sectional view of an example of a fluororesin-coated metal plate according to the present invention. The fluororesin-coated metal plate of the embodiment shown in FIG. 1 is provided on at least one surface 1a of the metal plate 1 via a colored resin layer 2 and a transparent adhesive layer 3 on the surface of the colored resin layer 2. It has the resulting fluororesin layer 4.

【0011】

Metal plate The material of the metal plate 1 is not particularly limited. For example, various metal plates such as cold-rolled steel plates, stainless steel plates, aluminum plates, copper plates, and titanium alloy plates are exemplified. The shape of the metal plate may be any of a cut plate sheet shape and a coil shape. The metal plate may be plated by a known method, and examples of the plated metal plate include a galvanized steel plate, a zinc-aluminum alloy plated steel plate, and an aluminum plated steel plate. The metal plate may be pretreated. As pretreatment, for example, cleaning treatment such as pickling, chemical degreasing, alkaline degreasing, sandblasting treatment, buffing treatment, wire brushing treatment, barrel treatment, mechanical treatment such as steel wool polishing treatment, activation of electrolytic etching treatment, etc. Examples thereof include chemical conversion treatments such as treatment, chromate treatment, phosphate treatment, and zinc phosphate treatment. The thickness of the metal plate as described above is not particularly limited. The type, shape, thickness, etc. of the metal plate may be selected according to the application of the fluororesin-coated metal plate.

【0012】

Colored resin layer A colored resin layer 2 that imparts design to the metal plate 1 is formed on at least one surface 1a of the metal plate 1. The colored resin layer 2 may be laminated directly on the metal surface 1a, or may be laminated via a primer layer 5 as described later. The colored resin layer is formed of a colored resin containing a resin component and a colorant. As the colored resin, a known paint can be used without particular limitation, and for example, a paint containing a polyester resin, a polyurethane resin, an acrylic resin, a fluororesin or the like as a main component can be used. Among these, a paint containing a polyester resin is preferably used.

【0013】

The colorant may be any of known color pigments such as carbon black, iron oxide and titanium oxide, bright pigments such as aluminum flakes, rust preventive pigments such as strontium chromate, and dyes, and is not particularly limited. Further, the colored resin layer 2 is a filler for paints commonly used for the purpose of adjusting the gloss and performance of the coating film, such as silica, synthetic silica, mica, talc, alumina, ceramics, silica balloons, and glass beads. , Calcium carbonate and other extender pigments may be included. The amount of the colorant in the colored resin layer 2 may be a range that can conceal the metal surface and impart designability, but the amount of the additive components such as the colorant, the filler, and the extender pigment is the amount of the colored resin layer 2. It affects the properties and, by extension, the performance of the fluororesin-coated metal plate. The total amount of added components in the colored resin layer 2 is preferably less than 70% by weight at the maximum. When the amount of the added component is 70% by weight or more, the colored resin layer tends to become brittle, and various performances such as adhesion and corrosion resistance of the finally obtained fluororesin-coated metal plate may deteriorate. More specifically, the total amount of the added components in the colored resin layer 2 is preferably about 5 to 50% by weight. The amount of the colorant varies depending on the color and the like, but is usually 10 to 100% by weight in the added component and about 0.5 to 50% by weight in the colored resin layer 2. The colored resin layer 2 can be formed by painting, drying, and baking a paint on the metal surface 1a or on the primer layer 5 provided as needed.

【0014】

In order to reduce the residual stress of the colored resin layer after processing and improve the adhesion after processing, the tensile elongation at break E of the colored resin layer 2_BIs preferably 5% or more. More preferably, it is 10% or more. As a method for increasing the tensile elongation at break, defining the thickness of the colored resin layer 2 is the most effective and important as described above, but in addition to this, the glass transition of the resin component constituting the colored resin layer 2 is performed. Examples include lowering the points, lowering the crosslink density, and reducing the amount of inorganic components including colorants.

【0015】

In the present invention, the thickness of the colored resin layer 2 is less than 10 μm. In the coating layer structure of the present invention, since the thickness of the colored resin layer 2 is less than 10 μm, the colored resin layer 2 cracks even when the fluororesin-coated metal plate is processed or used under harsh conditions. Alternatively, the effect that peeling from the metal surface is unlikely to occur is exhibited. The minimum value of the film thickness that exhibits such an effect is selected from the viewpoint of concealing the metal surface and imparting designability, but a particularly preferable film thickness range is 2 to 8 μm, and more preferably 3 to 7 μm. Is. When the film thickness is 10 μm or more, peeling and cracking are likely to occur, and the appearance and corrosion resistance tend to deteriorate.

【0016】

Adhesive layer The adhesive layer 3 is formed of a transparent adhesive. Here, "transparent" means that visible light is transmitted, and means that the color of the colored resin layer 2 can be visually observed through the adhesive layer 3 and the fluororesin layer 4. As the above-mentioned adhesive, a known adhesive can be widely used as long as it is transparent and has adhesiveness to the colored resin layer 2 and the fluororesin layer 4, and the form of the adhesive is not particularly specified. For example, a liquid type using water or an organic solvent as a medium, or a hot melt type can be used.

【0017】

Specifically, adhesives containing resin components such as rubber-based, urethane-based, urethane-epoxy-based, polyurethane elastomer-based, epoxy-based, polyester-based, acrylic-based, and silicon-based adhesives can be used. Among these, those containing the same type of resin component as the colored resin layer 2 are preferable, and specifically, an adhesive containing a polyester-based resin component is most suitable. Further, it is preferable that the glass transition point Tg of the resin component is 0 to 30 ° C. This is because when Tg is less than 0 ° C, the cohesive force of the adhesive layer may be insufficient, while when it exceeds 30 ° C, the adhesive layer tends to become brittle and easily cracked.

【0018】

Further, the adhesive is preferably crosslinkable. Specifically, the adhesive may contain a cross-linking agent such as a melamine-based, isocyanate-based, epoxy-based, amine-based, or peroxide-based adhesive, or may contain a resin component having a self-crosslinking functional group. .. Further, a cross-linked form by light such as ultraviolet rays or an electron beam may be used.

【0019】

The thickness of the adhesive layer 3 is not particularly specified, but is preferably 0.5 to 15 μm, particularly preferably 2 to 10 μm. With such a thickness, a transparent and sufficient adhesive force is usually obtained. If the thickness of the adhesive layer exceeds 15 μm, the transparency may be impaired, and the processability of the finally obtained fluororesin-coated metal plate may be deteriorated.

【0020】

Fluororesin layer In the present invention, the fluororesin layer 4 is provided on the outermost surface layer of the coating layer via the adhesive layer 3, and the fluororesin layer 4 is formed of a perfluoro-type fluororesin. The perfluorofluororesin may have an oxygen bond such as an ether bond, but refers to a fluororesin in which a hydrogen atom is not bonded to carbon in the polymerization unit. Specifically, polytetrafluoroethylene (specifically, polytetrafluoroethylene () PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), etc.

【0021】

In the case of a general colored resin-coated metal plate that does not have a fluororesin layer, the colored resin layer is the outermost layer of the product, so that various performances such as hardness, gloss, color tone, and corrosion resistance of the colored resin layer are satisfied. In addition, it is often necessary to take measures such as increasing the glass transition point and cross-linking density of the resin, blending an inorganic component other than the colorant, and thickening the colored resin layer and the primer layer described later. However, in the fluororesin-coated metal plate of the present invention, the above-mentioned measures are unnecessary because the outermost layer is a perfluorofluororesin.

【0022】

Fluororesin is generally excellent in various properties such as corrosion resistance, stain resistance, heat resistance, non-adhesiveness, nonflammability, chemical resistance, weather resistance, and processability. In the present invention, such fluorine is used. Among the resins, by using a perfluorofluororesin in particular, it is possible to obtain an effect that the slipperiness during processing is particularly improved and the adhesion is not lowered even after processing. That is, since the slipperiness during processing is excellent, damage due to residual stress and shrinkage force applied to the colored resin layer 2 can be reduced, and excellent adhesion can be maintained even after processing.

【0023】

The thickness of the fluororesin layer is usually preferably 5 to 100 μm, particularly preferably 10 to 30 μm. If the thickness is less than 5 μm, the performance such as corrosion resistance and stain resistance may be insufficient, while if the thickness exceeds 100 μm, various characteristics are saturated, which is economically disadvantageous. In addition, the processability of the finally obtained fluororesin-coated metal plate deteriorates, and a large stress is applied to the colored resin layer due to the expansion and contraction of the fluororesin layer under a long-term use environment, resulting in adhesion and adhesion. This is because it may cause a decrease in corrosion resistance.

【0024】

The most convenient and preferable method for forming the fluororesin layer 4 is to laminate the fluororesin, which has been processed into a film in advance, on the colored resin layer 2 via the adhesive layer 3, but the method is limited to this. Any means may be used, such as a method of dispersing or dissolving a fluororesin in a medium for coating, a method of hot-melting and laminating a fluororesin, or a method of coating and heating a powdered fluororesin.

【0025】

When the fluororesin film is used, it is desirable to modify the surface of the adhesive surface of the film in advance in order to improve the adhesion to the adhesive layer. As the surface modification method, a corona discharge treatment, a plasma discharge treatment, a sputter etching treatment, a fire treatment, an ozone treatment, a dry treatment such as an ionization active ray treatment, and a wet treatment such as a chemical treatment can be used. Further, as long as the effect of the present invention is not impaired, it is also effective to introduce a functional group into the fluororesin molecule or to blend the polymer with another polar resin in terms of improving the adhesiveness.

【0026】

Further, the fluororesin film may be either a single layer body or a multilayer body. In the case of a multilayer body, the outermost surface layer of the finally obtained fluororesin-coated metal plate may be a fluororesin, and the surface to be adhered to the adhesive layer may be made of another resin. The fluororesin layer 4 as described above may be transparent enough that the color of the underlying colored resin layer 2 can be visually observed through the adhesive layer 3, and is slightly colored as long as the design is not impaired. It may be colored, or it may be colored for the purpose of imparting design.

【0027】

The fluororesin-coated metal plate according to the present invention may have a primer layer 5 between the metal plate 1 and the colored resin layer 2, and such an embodiment is shown in FIG. In FIG. 2, the configuration except for the primer layer 5 is the same as that in FIG. 1, and the description of the components having the same reference numerals as those in FIG. 1 is omitted.

【0028】

The primer layer 5 is provided as necessary in order to improve the adhesion and corrosion resistance between the metal plate 1 and the colored resin layer 2. As the primer, a known primer containing an evoxy resin or a polyester resin as a main component can be used without particular limitation. Further, the primer layer 5 may contain a rust preventive pigment such as strontium chromate and other chromic acid compounds, if necessary. The suitable film thickness of the primer layer is usually 0.5 to 5 μm, more preferably 0.5 to 3 μm.

【0029】

When the primer layer 5 is provided, it is desirable that the combined film thickness of the colored resin layer 2 and the primer layer 5 is less than 12 μm. When the total film thickness is 12 μm or more, peeling and cracking are likely to occur, and the appearance and corrosion resistance tend to deteriorate. A more preferred total film thickness is less than 10 μm.

【0030】

The fluororesin-coated metal plate according to the present invention may have a printed layer 6 such as a pattern and characters on the surface of the colored resin layer 2 and / or the surface 4 of the fluororesin layer 4. FIG. 3 shows an example in which the printed layer 6 is provided on the surface of the colored resin layer 2, FIG. 4 shows an example in which the printed layer 6 is provided on the surface 4 of the fluororesin layer 4, and FIG. 5 shows an example of the surface of the colored resin layer 2. This is an example in which the printing layer 6 is provided on the surface 4 of the fluororesin layer. In each of these figures, the components having the same reference numerals as those in FIGS. 1 and 2 have the same configurations as those in FIGS. 1 and 2.

【0031】

Although the examples of the fluororesin-coated metal plate have been described above with reference to the drawings, the fluororesin-coated metal plate according to the present invention is not limited to these examples. The design of the fluororesin-coated metal plate according to the present invention is such that not only the colored resin layer 2 but also the colors and patterns of the colored resin layer 2, the adhesive layer 3, the fluororesin layer 4 and the printing layer 6 are overlapped. It can also be expressed by. Further, the coating layer of the metal plate may be provided on at least one surface 1a of the metal plate 1, the other surface (not shown) may remain as a metal surface, and a coating layer similar to the surface 1a may be provided. It may be provided, or a part of the layers constituting the coating layer may be provided.

【0032】

As described above, the fluororesin-coated metal plate according to the present invention has a coating layer having excellent adhesion on the metal surface, is less likely to cause peeling, cracking, etc., and can be used or processed in a harsh environment. Such adhesion and corrosion resistance are exhibited. By limiting the thickness of the colored resin layer and forming the fluororesin layer with a specific fluororesin, the mechanical properties of the colored resin layer are improved, and each resin layer is accompanied by a change in the usage environment for a long period of time. In particular, the influence of stress changes such as residual stress and shrinkage force of the fluororesin layer or stress changes during molding on the colored resin layer is alleviated, and the colored resin layer maintains high adhesion without breaking or peeling. It is inferred that.

【0033】

Production method Next, an example of the method for manufacturing the fluororesin-coated metal plate according to the present invention will be specifically shown with reference to FIG. First, dirt such as oil and dust on the surface of the metal plate 1 is removed, and if necessary, pretreatment such as chemical conversion treatment is performed. If necessary, a primer paint is applied to at least one surface 1a of the metal plate 1, dried, and baked to form a film, and the primer layer 5 is formed on the metal plate. Next, a colored paint is applied onto the primer layer 5, dried, and baked to form a film to form the colored resin layer 2. A transparent adhesive is applied onto the colored resin layer 2 and dried to form the adhesive layer 3. Finally, the adhesive layer 3 is adjusted to a soft state by heating or the like, a fluororesin film is attached onto the adhesive layer 3, and the adhesive layer 3 and the fluororesin film are adhered to each other by pressure bonding with a pair or more rolls. The resin layer 4 is formed. Alternatively, an adhesive may be applied to the fluororesin film in advance, and the adhesive surface side may be bonded to the colored resin layer 2 for lamination.

【0034】

In the above, the primer layer, the colored resin (paint) layer, and the adhesive layer are formed by using conventionally known coating methods such as dipping, spraying, brush coating, roll coater, air knife, and electrostatic coating, respectively. Can be done. Further, the fluororesin film can be bonded by a press method other than the roll.

【0035】

Each layer such as the primer layer, the colored resin layer, the adhesive layer, and the fluororesin layer in the present invention is a high molecular weight material such as wax or resin, an inorganic fiber, an inorganic filler, or a metal as long as the object according to the present invention is not impaired. Fillers such as powders and extender pigments, coloring pigments, dyes, coloring agents such as inks, scratch inhibitors, light stabilizers, antifungal agents, antibacterial agents, antioxidants, antioxidants, silane coupling agents, and adhesiveness Additives such as an agent and a reaction catalyst may be contained as required. Further, a leveling agent, a dispersant, an anti-repellent agent, an anti-color separation agent, an anti-sedimentation agent, a surfactant, an antifoaming agent and the like can be added to the paint for forming each resin layer as needed. ..

【0036】

[Example]

Next, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. (Example 1) A fluororesin-coated metal plate having the configuration shown in FIG. 1 was prepared. Coated chromate treatment (50 mg / m in terms of chromium adhesion) on one side of a coiled hot-dip galvanized steel sheet 1 (weight Ζ25) with a thickness of 0.5 mm.²) Was given. A colored resin paint (containing 10% by weight of cream-colored pigment) containing a melamine crosslinked polyester resin as a main component was applied to the chemical conversion surface 1a using a roll coater, and then baked at 210 ° C for 30 seconds to a thickness of 8 μm. A steel strip on which the colored resin layer 2 (pigment content in the layer was 30% by weight) was laminated was obtained.

【0037】

Next, on the surface of the colored resin layer 2, a transparent polyester-based adhesive dissolved in an organic solvent (containing a polyester resin having a glass transition point of 20 ° C and an isocyanate cross-linking agent) is applied, and the film thickness after drying becomes 5 μm. As described above, the coating was applied using a roll coater and baked at 200 ° C. for 50 seconds to form the adhesive layer 3. Immediately after baking, the adhesive layer 3 is in a molten state. While the temperature drops, a transparent tetrafluoroethylene-hexafluoropropylene copolymer (FEP) film 4 with a thickness of 25 μm (adhesive surface is pre-discharged). Was bonded and bonded using a pair of metal rolls. The obtained fluororesin-coated metal plate was subjected to various performance tests as shown below. The results are shown in Table 1. The performance test method is shown below.

【0038】

(1) Adhesion [Primary adhesion] After cutting a grid (5 x 5 at a pitch of 2 mm) on the coating layer side of the test piece to a depth that reaches the metal plate, Eriksen is stretched by 10 mm, and the primary adhesion is evaluated by a tape peeling test. did. [Secondary adhesion] Another test piece is immersed in boiling water for 5 hours in a flat plate state, and then the grid is cut and Eriksen overhang is performed in the same manner as described above to improve the secondary adhesion by the tape peeling test. evaluated. [Adhesion evaluation] When the number of peels was 0, it was evaluated as , when it was 1 to 5, it was evaluated as , when it was 6 to 10, it was evaluated as Δ, and when it exceeded 11, it was evaluated as ×.

【0039】

(2) Corrosion resistance The test piece was bent and molded at a right angle using a roll at a processing speed of 30 m / min with the fluororesin layer side of the test piece on the outside. In the bent state, a salt spray test was conducted for 1000 hours at 5% saline solution and a temperature of 35 ° C in accordance with JIS Ζ2371, and the presence or absence of rust after the test was evaluated. The case where there was no abnormality was evaluated as , the case where rust was generated in a part of the bent part was evaluated as , the case where rust was generated in the entire bent part was evaluated as Δ, and the case where rust was generated in the flat plate part was evaluated as ×.

【0040】

(3) Workability At room temperature, the test piece was bent at 180 ° with the fluororesin layer side on the outside, and the presence or absence of cracks in the coating film and film at the bent portion was observed with a microscope. The case where there was no abnormality was evaluated as , the case where a slight crack was observed was evaluated as Δ, and the case where a remarkable crack was observed was evaluated as ×.

【0041】

(4) Heat resistance The test piece was heated in air at 180 ° C for 15 minutes and then cooled to room temperature. After repeating this 20 times, the presence or absence of peeling, shrinkage, discoloration, etc. of the fluororesin film was confirmed. The case where there was no abnormality was evaluated as , and the case where any abnormality was observed was evaluated as ×.

【0042】

(5) Contamination resistance Contact each of hair tonic, hair liquid, black magic ink, coffee, tea, mayonnaise, ketchup, soy sauce, sauce, wasabi, and mustard on the fluororesin film surface side of the test piece at room temperature for 1 week, and then ethanol. Was wiped off with moistened cotton and the state of adhesion was investigated. When the test piece was completely removed by one wiping and the test piece was not contaminated at all, it was judged as , when it was not contaminated but required to be wiped twice or more, it was judged as , and when it was contaminated, it was judged as ×.

【0043】

(Examples 2 to 6) In Example 1, the fluororesin was the same as in Example 1 except that the thickness of the colored resin layer and the fluororesin layer resin type (type of fluororesin film) were changed as shown in Table 1. A coated metal plate was prepared and various performance tests were performed. The results are shown in Table 1.

【0044】

(Comparative Examples 1 and 2) In Example 1, a fluororesin-coated metal plate was prepared in the same manner as in Example 1 except that the thickness of the colored resin layer was changed as shown in Table 1, and various performance tests were performed. .. The results are shown in Table 1.

【0045】

(Comparative Example 3) A fluororesin-coated metal plate was prepared in the same manner as in Example 2 except that the fluororesin layer resin was a tetrafluoroethylene-ethylene copolymer (ETFE), and various performance tests were conducted. The results are shown in Table 1.

【0046】

(Example 7) A fluororesin-coated metal plate having the configuration shown in FIG. 2 was prepared. In Example 1, before applying the colored resin paint, a primer paint (containing strontium chromate) containing evoxy resin as a main component is coated on the chemical conversion treated surface using a roll coater, and baked at 210 ° C. for 30 seconds. A fluororesin-coated metal plate was prepared in the same manner as in Example 1 except that the primer layer 5 having a thickness of 3 μm was coated, and various performance tests were performed. The results are shown in Table 1.

【0047】

(Examples 8 to 9) In Example 7, the thickness of the primer layer and the colored resin layer and the fluororesin layer resin type (type of fluororesin film) were changed as shown in Table 1 in the same manner as in Example 7. A fluororesin-coated metal plate was prepared and various performance tests were conducted. The results are shown in Table 1.

【0048】

(Example 10) A fluororesin-coated metal plate having the configuration shown in FIG. 4 was prepared. A fluororesin-coated metal plate was prepared in the same manner as in Example 9 except that the PFA film adhesive surface side was preliminarily printed in dots with white ink, and various performance tests were performed. The results are shown in Table 1.

【0049】

(Comparative Examples 4 to 6) In Example 7, the thickness of the primer layer and the colored resin layer and the fluororesin layer resin type (type of fluororesin film) were changed as shown in Table 1 in the same manner as in Example 7. A fluororesin-coated metal plate was prepared and various performance tests were conducted. The results are shown in Table 1.

【0050】

[table 1]

<img file="JP2000117889A_D0001.tif" />【0051】

It can be seen from the above examples that the fluororesin-coated metal plate according to the present invention has high adhesion and is excellent in various properties such as corrosion resistance, stain resistance, heat resistance, non-mucosal property, and processability. .. Further, in each of the examples, the color of the colored resin layer could be visually observed through the fluororesin layer, and the design was excellent. On the other hand, the fluororesin-coated metal plate according to the prior art shown in the comparative example is inferior in various performances such as corrosion resistance.

【0052】

[Effect of the invention]

As described above, the fluororesin-coated metal plate according to the present invention has a coating layer having a specific structure having excellent adhesion. This coating layer does not deteriorate in adhesion not only immediately after production but also after being molded or used for a long period of time in a harsh environment, and does not crack or peel off from the metal plate. Therefore, the fluororesin-coated metal plate retains designability and corrosion resistance for a long period of time, and can sufficiently exhibit various properties peculiar to fluororesin such as stain resistance, heat resistance, and non-adhesiveness. It is suitably used for various interior and exterior building materials, kitchen-related applications, and electrical and electronic-related applications.

[Simple explanation of drawings]

[Figure 1]

It is a partial cross-sectional view of the aspect example of the fluororesin-coated metal plate which concerns on this invention.

[Figure 2]

It is a partial cross-sectional view of the aspect example of the fluororesin-coated metal plate which has a primer layer.

[Fig. 3]

It is a partial cross-sectional view of the aspect example of the fluororesin-coated metal plate which has a printing layer.

[Fig. 4]

It is a partial cross-sectional view of the aspect example of the fluororesin-coated metal plate which has a printing layer.

[Fig. 5]

It is a partial cross-sectional view of the aspect example of the fluororesin-coated metal plate which has a printing layer.