JP2000309066A - Weatherable resin-coated metal panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weatherable resin coated metal panel capable of sufficiently suppressing the deterioration of a vinyl chloride resin coated metal panel by ultraviolet rays over a long period of time. SOLUTION: In a resin coated metal panel constituted by providing a vinyl chloride resin layer 3 on a substrate metal panel 1 and further laminating a transparent resin film 5 containing an ultraviolet absorber on the resin layer 3, a layer 4 having function for preventing the transfer of the ultraviolet absorber is provided between the vinyl chloride resin layer 3 and the transparent resin film 5 containing the ultraviolet absorber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated metal plate used for outdoor applications and having improved weather resistance, and more particularly, to a vinyl chloride resin having a transparent resin film to which an ultraviolet absorber is added and laminated on the surface. By providing a layer having a function of preventing migration of the ultraviolet absorber between the transparent resin film containing the ultraviolet absorber and the vinyl chloride resin layer on the metal plate, the ultraviolet absorber in the transparent resin film is provided. The present invention relates to a weather-resistant resin-coated metal plate capable of suppressing the attenuation of a protective effect due to migration of a metal and preventing discoloration and peeling over a long period of time.

[0002]

2. Description of the Related Art Among resin-coated metal plates used for outdoor applications, a vinyl chloride-based resin-coated metal plate having a pattern printed thereon for the purpose of imparting a design property is provided with a printed layer of a pattern. In general, a transparent resin film having good weather resistance is laminated on a vinyl resin film, and an acrylic resin or a fluorine resin is used as the transparent film having good weather resistance. This is to protect the printing layer and the underlying vinyl chloride resin layer from UV deterioration by adding an ultraviolet absorber to the transparent resin film to protect the thin printing layer from external force.
Also, by making the outermost surface a resin having good weather resistance, surface roughness due to deterioration is prevented.

[0003]

However, the transparent resin film used for lamination on the outer surface generally has a thickness of 25-10.
It is about 0 μm, and its ultraviolet shielding ability is not always sufficient. Increasing the amount of the ultraviolet absorber added to improve this, in the case of a film made of a resin poorly compatible with the ultraviolet absorber such as a fluororesin,
Immediately as a blow-off from the surface, it dissipates and, even in resins with excellent compatibility with UV absorbers such as acrylic resins, the UV absorber migrated to the vinyl chloride resin layer relatively early, and was expected. Not as effective.

Therefore, a so-called high-molecular-weight (or also referred to as polymer-type) ultraviolet absorber obtained by copolymerizing an ultraviolet absorber having a reactive unsaturated ethylene group and a monomer such as an alkyl (meth) acrylate is used as an acrylic absorber. Addition to a transparent film made of a base resin has been studied. Although this polymer type ultraviolet absorber has no problem of migration to a vinyl chloride resin layer as compared with a general ultraviolet absorber, the absorption efficiency of ultraviolet light is high because there are many portions not involved in ultraviolet absorption in the molecule. Bad, thickness 25 ~ 100μm
A large amount of addition is required to give a sufficient ultraviolet shielding effect to the transparent film of the class, and as the cost increases,
There is a possibility that the handleability may be deteriorated or the workability may be deteriorated due to the deterioration of the film physical properties.

[0005]

The present invention has solved these problems. The gist of the present invention is to provide a vinyl chloride resin layer on a base metal plate and further include an ultraviolet absorber on the vinyl chloride resin layer. In a resin-coated metal plate having a configuration in which a transparent resin film is laminated, a layer having a function of preventing migration of the ultraviolet absorber is provided between the vinyl chloride resin layer and the transparent resin film containing the ultraviolet absorber. A feature is a weather-resistant resin-coated metal plate.

The transparent resin film containing the above-mentioned ultraviolet absorber comprises a flexible (meth) acrylate resin obtained by graft polymerization of a (meth) acrylate resin monomer with a crosslinked elastic component as a core. Is a weather-resistant resin-coated metal plate having a UV-shielding property in a wavelength range of 280 to 400 nm measured at a half of the actual coating thickness of the transparent resin film containing the ultraviolet absorber. Is a weather-resistant resin-coated metal plate having a measured value of 60% or more.

The layer having the function of preventing the transfer of the ultraviolet absorber is made of a modified acrylic resin, and is formed of both a vinyl chloride resin layer and a transparent resin film mainly composed of a flexible (meth) acrylate resin. Is a weather-resistant resin-coated metal plate having a thickness of 2 to 10 μm and a layer having a function of preventing the migration of an ultraviolet absorber, and a transparent resin film and an ultraviolet absorber. And a printing layer provided between a layer having a function of preventing the transfer of an ultraviolet absorbent and a layer of a vinyl chloride resin.

[0008]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing one embodiment of the weather-resistant resin-coated metal plate of the present invention. FIGS. 2 and 3 are schematic cross-sectional views showing another embodiment of the weather-resistant resin-coated metal plate of the present invention. FIG.

In the present invention, as shown in FIG. 1, a vinyl chloride resin layer 3 is laminated on a base metal plate 1 with an adhesive 2 interposed therebetween, and further has a function of preventing the transfer of an ultraviolet absorber. It has a configuration in which a transparent resin film 5 to which an ultraviolet absorber is added is laminated with a layer 4 interposed therebetween. The base metal plate 1 used for the weather-resistant resin-coated metal plate of the present invention generally refers to a metal plate used as a base material of the resin-coated metal plate. Examples include a galvanized steel sheet, an aluminum / zinc composite plated steel sheet, an aluminum plated steel sheet, a stainless steel sheet, and an aluminum-based alloy sheet. There is no particular limitation on the thickness, heat treatment conditions, plating thickness, and the like of the base metal plate 1, and the surface treatment of the base metal plate 1 is performed by a phosphate treatment, a chromate treatment, or the like. Is also good.

A resin layer 3 is laminated on the base metal plate 1 with an adhesive layer 2 interposed therebetween. Adhesives that can be used for this include acrylic adhesives, urethane adhesives, acrylic / urethane adhesives, epoxy adhesives, phenolic adhesives, amide adhesives, acid-modified olefin adhesives, vinyl acetate Adhesives, polyester adhesives, copolyester adhesives, copolyamide adhesives, and the like, and mixtures thereof.

The method of applying and baking the adhesive may be a method generally used for the production of a resin-coated metal plate. For example, an adhesive dissolved in a solvent is applied by a roll coater.
After continuous application onto the unwound steel sheet coil, a method of introducing it into a drying furnace installed in-line and then into a baking furnace can be used.

A vinyl chloride resin sheet or a vinyl chloride sol coat used for the vinyl chloride resin layer 3 may be a general one used for a resin-coated metal plate, and has a thickness of about 100 to 200 μm. Can be used.

Layer 4 having function of preventing migration of ultraviolet absorber
The (transition preventing layer) is a thin film, and is not limited as long as it is interposed between the transparent resin film 5 to which the ultraviolet absorber is added and the vinyl chloride resin layer 3 and can reduce or prevent the migration of the ultraviolet absorber. Although it can be used, it is generally composed of a resin having poor compatibility with the ultraviolet absorber. Alternatively, there may be mentioned those having an action such that a molecule of an ultraviolet absorbent cannot be transmitted due to adopting a crosslinked structure. Further, it is preferable that a special adhesive is not required for providing the migration preventing layer 4 in terms of simplification of the structure, suppression of cost increase, and avoiding danger of peeling after exposure. It is preferable that the layer 4 itself has excellent adhesion to the transparent resin film 5 and the vinyl chloride resin layer 3.

An example of a preferable material for the migration preventing layer 4 is Polyment NK-380 (Nippon Shokubai Co., Ltd.). Polyment NK-380 is commercially available as a plasticizer migration inhibitor, and is applied to the surface of a vinyl chloride resin film to prevent deterioration of the surface appearance due to bleed-out (surface deposition) of the plasticizer and to prevent dust. The adhesive is applied between the film of the vinyl chloride resin film having the pressure-sensitive adhesive layer such as a marking film and the pressure-sensitive adhesive layer, and the plasticizer is transferred to the pressure-sensitive adhesive layer. Uses such as preventing the adhesive from deteriorating have been proposed.

The polyment NK-380 is made of a modified acrylic resin and has excellent adhesiveness to a resin which is generally hard to adhere, so that a fluorine resin film and a vinyl chloride resin film are used. Alternatively, use as an adhesive with a base material such as a metal has also been proposed. However, there is no mention of the effect of preventing the transfer of the ultraviolet absorbent as in the present invention. The Polyment NK
When -380 is used as the layer for preventing the migration of the ultraviolet absorbent, the preferable coating thickness is in the range of 2 to 10 [mu] m in terms of the dry film thickness. No improvement effect is seen, and even if the thickness is larger than this, not only the migration preventing effect is saturated, but also the workability in the configuration of the resin-coated metal plate is reduced, and during the cohesion peeling in the migration preventing layer, etc. Problem occurs, which is not preferable.

The minimum required thickness is a transparent resin film 5
Although it may vary depending on the molecular weight and the amount of the ultraviolet absorber added therein, the thickness is generally about 5 μm, so that even when a large amount of the ultraviolet absorber having a low molecular weight is added, the migration is effectively prevented. obtain. In addition, the polyment NK-3
Since 80 is a modified acrylic resin, it has good adhesiveness with vinyl chloride resin and, as described above, also has excellent adhesiveness with various hardly-adhesive resins. It is also possible to use a fluorine-based resin having good weather resistance.

However, the fluorine-based resin generally has poor compatibility with the ultraviolet absorber, and even when the migration-preventing layer 4 is provided between the fluorine-based resin and the vinyl chloride-based resin layer 3, the dissipation from the outside air side surface does not occur. It is considered to be remarkable, and from that point, it is preferable to use an acrylic resin having excellent compatibility with an ultraviolet absorber and relatively good weather resistance as the transparent resin film 5.

As the transparent acrylic resin film, an acrylic film containing a crosslinked acrylic rubber component generally called "soft acrylic" or "flexible acrylic" is suitably used, and various commercially available films can be used. . The preferred thickness of the transparent acrylic resin film is 2
It is preferable to select in the range of 0 to 100 μm. If the thickness is smaller than this, it is difficult to impart an effective ultraviolet shielding property to the film. If the thickness is larger than this, the workability of the resin-coated metal plate is lowered and the cost is increased.

Further, one surface of the transparent acrylic resin film (the surface opposite to the surface on which the migration preventing layer 4 is provided) is provided with further weather resistance, stain resistance, chemical resistance and the like. A film to which another resin layer is added for the purpose or a film in which another resin having compatibility with the acrylic resin is blended can be considered to be included in the category of the acrylic resin film.

As the ultraviolet absorber added to the transparent resin film 5, various commercially available ultraviolet absorbers can be used without limitation. When an acrylic resin film is used as the transparent resin film 5, even if a relatively low-cost ultraviolet absorber having a low molecular weight is used, good weather resistance can be obtained by providing the migration prevention layer 4. It is preferable to select a preferable addition amount of the ultraviolet absorber in a range of 0.5 to 10.0 parts by weight based on 100 parts by weight of the base resin forming the film. If the amount is less than 0.5 part by weight, an effective ultraviolet shielding property cannot be obtained in a practical thickness, and if the amount is more than 10.0 parts by weight, the appearance is deteriorated due to blowing from the outer surface of the film, which is not preferable.

A more preferable addition amount of the ultraviolet absorber is a measured value of the ultraviolet shielding property in a wavelength range of 280 to 400 nm measured at a half of the actual coating thickness of the transparent resin film containing the ultraviolet absorber. That is, it is added so as to be 60% or more. This is because no matter how effectively the migration preventing layer 4 functions, if the amount of the ultraviolet absorber contained in the transparent resin film 5 is initially insufficient, good weather resistance cannot be obtained. Stipulates a sufficient ultraviolet shielding property as an initial value. However, it is not theoretical that the "ultraviolet ray shielding property" measured by the method is set to be 60% or more, but is based on experience.

As shown in FIG. 2 or FIG. 3, between the vinyl chloride resin layer 3 and the migration preventing layer 4, or between the transparent resin film 5 and the migration preventing layer 4, A pattern printing layer 6 such as a pattern may be provided. As a method for providing the print layer, a commonly used printing method can be used. As an example, a method such as using an acrylic resin-based binder ink with a gravure coater can be used. The thickness of the print layer 6 may be in a general range of 1 to 10 μm, and full-printing or partial printing may be used. The positional relationship between the print layer 6 and the migration prevention layer 4 and whether the whole is laminated and integrated after being applied to the back surface of the transparent resin film 5 or the surface of the vinyl chloride resin layer 2 may be arbitrarily determined.

[0023]

Embodiments of the present invention will be described below. Each sample used in Examples 1 to 5 and Comparative Examples 1 to 4 was prepared by the following procedure. -Preparation of transparent resin film 5 containing ultraviolet absorbent Commercially available flexible acrylic pellets and the type and amount of ultraviolet absorbent shown in Table 1 were respectively fed to a twin-screw extruder using two quantitative feeders. After being supplied and extruded from a strand die, it is made into a flexible acrylic pellet containing an ultraviolet absorbent using a pelletizer, and this is put into a single screw extruder and extruded from a T die to have a thickness of 5 mm.
At the same time as obtaining the transparent acrylic resin film 5 having a thickness of 0 μm, the transparent acrylic resin film 5 having the same content and having a thickness of 25 μm for measuring the ultraviolet shielding property at a half thickness was obtained. Table 1 below shows Examples 1 to 5 of the present invention and Comparative Example 1.
4 to 4 show the types of ultraviolet absorbers used and the values of the amounts added.

[0024]

[Table 1]

The application of a layer 4 having an effect of preventing the transfer of the ultraviolet absorber The modified acrylic resin-based coating agent “Polyment NK-380” manufactured by Nippon Shokubai Co., Ltd.
dry thickness of 1 μm, 2 μm on one surface of the transparent acrylic resin film 5 (the surface on the side laminated with the vinyl chloride resin layer 3).
After coating with a bar coater so as to have a thickness of 5 μm, 5 μm and 10 μm, the film was placed in a hot-air oven while keeping the film from shrinking, and allowed to dry at 105 ° C. for 2 minutes. At the same time, dry thicknesses of 1 μm and 2 μm were similarly formed on both sides of the transparent acrylic resin film 5 of 25 μm prepared above.
m, 5 μm, and 10 μm, and used as a sample to evaluate the migration of the ultraviolet absorbent to the vinyl chloride resin 3.

Preparation of Soft Vinyl Chloride Resin Used for Vinyl Chloride Resin Layer 3 100 parts by weight of polyvinyl chloride resin having an average degree of polymerization of 1050, and dioctyl phthalate (DOP) as a plasticizer
35 parts by weight, 2 parts by weight of epoxidized soybean oil, 7 parts by weight of a total of a lead-based stabilizer and a Ba-Zn-based stabilizer as stabilizers, and 8 parts by weight of titanium oxide as a pigment, having a diameter of 8 inches. And kneaded with two parallel heating rolls to obtain a film having a thickness of 200 μm. The same vinyl chloride resin layer 3 was used in all of the examples and comparative examples.

Preparation of Resin-Coated Metal Sheet Acrylic adhesive 2 was applied to one side of hot-dip galvanized steel sheet 1 having a thickness of 450 μm and surface-treated with phosphoric acid so as to have a thickness of 5 μm after drying. At the same time as baking, a laminate obtained by combining the above-mentioned vinyl chloride resin layer 3, various transparent acrylic resin films 5, and migration prevention layers 4 of various thicknesses in combination as shown in Table 2 below,
It was laminated on the adhesive layer 2 of this steel sheet. The layer provided with the migration preventing layer 4 is laminated so that the layer 4 is located between the layer 3 and the layer 5.

[0028]

[Table 2]

The time-dependent change of the ultraviolet shielding property due to the transfer to the vinyl chloride resin layer 3: a transparent acrylic prepared to have a thickness (in this case, 25 μm) of the thickness actually coated on the vinyl chloride resin layer 3 As a measurement sample, a migration-preventing layer 4 having the same thickness as in Examples 1 to 5 and Comparative Examples 1 to 3 on both surfaces of the base resin films 5-1 and 5-2 (or not) is used. (Hereinafter, the types of the measurement samples are referred to by the numbers of the corresponding Examples and Comparative Examples).

紫外線 Ultraviolet ray shielding property: 280 to 4 out of absorption waveforms measured by a spectrophotometer (see FIG. 4: maximum sensitivity = transmittance 0.01%) whose light transmittance is shown on a logarithmic scale.
The area formed by the portion corresponding to the ultraviolet region of 00 nm is determined, and the transmittance is 0.01% or less over the entire wavelength range (the shielding in this case is assumed to be 100%).
The value obtained by expressing the ratio to the area of the sample as a percentage is referred to as “ultraviolet shielding property (%)”. The reason why the measurement is performed at half of the actual thickness is that a very small difference in the amount of transmitted ultraviolet light below the detection sensitivity of the measuring device causes a difference in the deterioration state of the vinyl chloride resin layer in long-term outdoor exposure. . Therefore, if a spectrophotometer with higher sensitivity can be obtained and the difference in the ultraviolet shielding property at the actual coating thickness can be compared, the measurement at the actual coating thickness may be performed, and the thickness is always specified to be 1/2. There is nothing to be done. Furthermore, in the case of a film using a resin having almost no absorption in the ultraviolet region of 280 to 400 nm, such as a film made of an acrylic resin, the amount of the ultraviolet absorber actually added is の of the amount of the ultraviolet absorber actually added. A method of preparing a film and measuring the film may be used.

Measurement of change over time in shielding properties due to migration: The above measurement sample was cut into a size of 40 mm × 40 mm, and a thickness of 6 mm was measured.
Two 00 μm vinyl chloride resin sheets (100 mm
× 100 mm: The composition is the same as that of the vinyl chloride resin film 3), and a 2 kg weight is placed on a plate sandwiched between the plating plates for pressing, and is allowed to stand in a hot air oven at 63 ° C. Until the lapse of 3000 hours, the change in the ultraviolet shielding property was measured every 1000 hours. This evaluation is to evaluate the effect of the migration preventing layer 4 at an early stage, such as a point that both surfaces of the acrylic resin film are sandwiched between the vinyl chloride resin films, a point that the thickness of the vinyl chloride resin film 3 is thick, and the like.
This is a measurement in a state where excessive migration is exhibited compared to the actual migration environment. The results are shown in Table 3 below and in FIGS.

[0032]

[Table 3]

"Case of acrylic film 5-1 containing general type ultraviolet absorber" As shown in Comparative Example 1, a large amount of an ultraviolet absorber having a relatively low molecular weight was added, and the initial stage of the ultraviolet shielding property was observed. Even if the value is increased, when the migration preventing layer 4 is not provided, the shielding property is gradually reduced due to migration to the vinyl chloride resin layer 3 and the effect is not persistent. In Comparative Example 3 in which the migration preventing layer 4 having a thickness of 1 μm was provided, the decrease in the shielding property was suppressed as compared with the case without the migration preventing layer. However, after 3000 hours, the shielding property was reduced to 55% of the initial value. It cannot be said that a good migration prevention property has been obtained. In contrast, in Example 1 in which the thickness of the migration preventing layer 4 was 2 μm, 80% of the initial value was maintained even after 3000 hours, and in Example 3 in which the thickness was 5 μm, the migration of the ultraviolet absorber was completely suppressed. Have been. In Example 5 in which the thickness was further increased to 10 μm, the same result as in the case of 5 μm was obtained.

"Case of Acrylic Film 5-2 Containing Dimer-Type Ultraviolet Absorber" An ultraviolet absorber called a dimer type has a relatively large molecular weight, and an atomic group involved in ultraviolet absorption in one molecule. Due to the presence of two groups, it has features such as excellent absorption efficiency per added amount. Therefore, an acrylic film 5 containing a general type ultraviolet absorber
-1 obtained a shielding initial value of 72% by the addition of 6 parts by weight, whereas the acrylic film 5 containing a dimer type
In -2, an initial value of 75% was obtained by adding 4 parts by weight. As shown in Comparative Example 2, the fact that the molecular weight of the ultraviolet absorber is large and that a high initial value of the shielding property can be obtained with a small amount of addition has an advantageous effect on the migration property, and the first 1000
At 0 hours, there is almost no decrease, but still 300
After 0 o'clock, it has dropped to 66% of the initial value. In the examples in which the migration preventing layer is provided, a sufficient migration preventing effect is obtained with a thinner migration preventing layer than in the case of the general type of ultraviolet absorber. Even in Example 4 in which the thickness of the migration preventing layer 4 is 5 μm, the initial value is maintained after 3000 hours.

The weather resistance of the resin-coated metal plate: Example 1
The accelerated exposure test (black panel temperature: 63 ° C.) by the Sunshine Weather Meter (Suga Test Instruments Co., Ltd.) was performed on the resin-coated metal plates of Comparative Examples 1 to 4 and 4000 by 4000
For 5000 hours and 6000 hours, visual observation of changes in appearance, measurement of color difference change (ΔE value), and visual observation of peeling of the coating resin were performed. The evaluation results are shown in Table 4 below and FIGS. 7 and 8.

[0036]

[Table 4]

At the time of 4000 hours of exposure, Comparative Example 1 in which a UV absorber having a low molecular weight was added to an acrylic film, and the migration preventing layer 4 was provided with a sufficient thickness, but the UV absorber was added from the beginning. The amount of discoloration was small and the discoloration was large in Comparative Example 4 having a low ultraviolet shielding property. In Comparative Example 1, cracks occurred on the acrylic surface,
In Comparative Example 2 in which a dimer-type ultraviolet absorber was added, loss of surface gloss was observed. On the other hand, in Examples 1 to 5 of the present invention in which the migration preventing layer 4 was provided between the transparent acrylic resin film 5 and the vinyl chloride resin layer 3, no change was observed in the surface appearance. With 5000 hours of exposure,
Also in Comparative Example 3 in which the migration preventing layer 4 was provided, the change in color difference was large, and it can be seen that a sufficient migration preventing effect was not obtained with a thickness of 1 μm. In the embodiment of the present invention in which the thickness of the migration preventing layer 4 is 2 μm or more, there is still little change in color difference, and there is no change in surface appearance or peeling. Exposure 6
In Example 1 in which a low molecular weight ultraviolet absorber was added to the acrylic film at 000 hours, the change in the color difference was slightly large, but in Comparative Examples 1 and 3 in which the same acrylic film was coated. In this case, peeling has occurred between the coating resin layer and the base metal 1, and the deterioration of the acrylic layer 5 is also progressing. The discoloration is also a much larger value than in the first embodiment.

Among these observed deteriorations, the discoloration is that the vinyl chloride resin layer 3 is deteriorated by the ultraviolet light transmitted through the transparent acrylic film, and the resulting deterioration product forms the acrylic film 5 and the vinyl chloride resin. It is considered that this is caused by accumulation near the interface of the layer 3. The peeling between the base metal 1 and the coating resin layer may also be caused by the hydrochloric acid generated by the deterioration of the vinyl chloride resin layer 3 corroding the metal surface, or by the deterioration product of the vinyl chloride resin layer 3 It is considered that this is caused by deterioration of the vinyl chloride resin layer 3 such as deterioration of the adhesive layer 2. Also, in the comparative example, the acrylic film, which should originally have much better weather resistance than the vinyl chloride resin, cracks relatively early. It is considered that the deterioration of the acrylic layer 5 is promoted by the deterioration product of the acrylic layer 5.

Here, Examples 1, 3, 5 and Comparative Example 1,
The initial value of the ultraviolet shielding property of the acrylic film 5 of No. 3 is exactly the same. Nevertheless, a large difference appears in the deterioration state after 6000 hours of accelerated exposure, because the attenuation of the shielding property due to the transfer of the ultraviolet absorber from the acrylic film 5 to the vinyl chloride resin layer 3 is due to the surface of the acrylic film. It shows that it occupies a considerable specific gravity among all the factors that decrease the shielding property, such as attenuation due to dissipation from the material, and attenuation due to decomposition in the acrylic film. As shown in Examples of the present invention, this vinyl chloride By preventing the transfer of the ultraviolet absorbent to the base resin layer 3, the weather resistance of the vinyl chloride resin base coated metal sheet for outdoor use can be effectively extended.

[0040]

The resin-coated metal plate of the present invention is a vinyl chloride resin-covered metal plate having a transparent resin film to which an ultraviolet absorber is added and laminated on the surface thereof. Since a layer having a function of preventing the transfer of the ultraviolet absorber is interposed between the vinyl resin layer and the protective resin, the attenuation of the protective effect due to the transfer of the ultraviolet absorber in the transparent resin film is suppressed, and the color is changed over a long period of time. Since it is a weather-resistant resin-coated metal plate capable of preventing peeling and peeling, it can be suitably used particularly for outdoor applications requiring weather resistance.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of a weather-resistant resin-coated metal plate of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the weather-resistant resin-coated metal plate of the present invention.

FIG. 3 is a schematic sectional view showing still another embodiment of the weather-resistant resin-coated metal plate of the present invention.

FIG. 4 is an explanatory diagram of the definition of the ultraviolet shielding property of the present invention.

FIG. 5 is a graph showing the relationship between the thickness of an ultraviolet (UV) absorbent migration-preventing layer and the change over time in ultraviolet shielding properties (using a transparent film 5-1).

FIG. 6 is a graph showing the relationship between the thickness of an ultraviolet absorber (UVA) migration preventing layer and the change over time in ultraviolet shielding properties (using a transparent film 5-2).

FIG. 7 is a diagram showing the relationship between the thickness of a UVA migration preventing layer and the change in color difference (using a transparent film 5-1).

FIG. 8 is a graph showing the relationship between the thickness of a UVA migration prevention layer and a change in color difference (using a transparent film 5-2).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base metal plate 2 Adhesive layer 3 Vinyl chloride resin layer 4 Layer having a function of preventing migration of ultraviolet absorber 5 Transparent resin film containing ultraviolet absorber 6 Printing layer

 ──────────────────────────────────────────────────の Continued on the front page F-term (reference) 4F100 AB01A AB03A AH02C AH02H AH03C AH03H AH07C AH07H AK01C AK15B AK25C AK25D AL06D AR00D BA04 BA07 BA10A BA10C BA13 CA07C GB07 HB31 JD20D JL00 JL00D

Claims (5)

[Claims] 1. A resin-coated metal plate having a structure in which a vinyl chloride resin layer is provided on a base metal plate and a transparent resin film containing an ultraviolet absorbent is further laminated thereon. A weather-resistant resin-coated metal plate, wherein a layer having a function of preventing migration of an ultraviolet absorbent is provided between the transparent resin film and the transparent resin film containing the ultraviolet absorbent. 2. A transparent (meth) acrylate-based resin obtained by graft-polymerizing a (meth) acrylate-based resin monomer with a crosslinked elastic component as a nucleus and comprising a transparent (meth) acrylate-based resin as a main component. Claim 1
3. The weather-resistant resin-coated metal plate according to claim 1. 3. A wavelength of 280 measured at a half of the actual coating thickness of a transparent resin film containing an ultraviolet absorber.
The weather-resistant resin-coated metal plate according to claim 1 or 2, wherein a measured value of the ultraviolet shielding property in a range of 400 nm is 60% or more. 4. A layer having a function of preventing migration of an ultraviolet absorber, which is composed of a modified acrylic resin, and which is both a vinyl chloride resin layer and a transparent resin film mainly composed of a flexible (meth) acrylate resin. The weatherable resin-coated gold sheet according to claim 2, wherein the layer having heat-fusing property and a layer having a function of preventing migration of the ultraviolet absorber has a thickness of 2 to 10 µm. 5. A printing layer is provided between a transparent resin film and a layer having a function of preventing migration of an ultraviolet absorber, or between a layer having a function of preventing migration of an ultraviolet absorber and a vinyl chloride resin layer. Item 5. A weather-resistant resin-coated metal sheet according to any one of Items 1 to 4.