JP2001315258A - Weather resistant resin-coated metal plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weather resistant resin-coated metal plate capable of sufficiently suppressing a deterioration of a polyolefin resin-coated metal plate with an ultraviolet ray for a long period. SOLUTION: The weather resistant resin-coated metal plate P comprises a colored polyolefin resin layer 2 and an ultraviolet absorbent-added transparent resin film 3 sequentially laminated on a base metal plate 1. In this case, adhesive layers 4 and 5 may be provided between the metal plate 1 and the resin layer 2 or between the resin layer 2 and the film 3. Alternatively, a print layer 6 may be provided between the layer 5 and the film 3. The resin layer 2 contains both a low molecular type ultraviolet absorbent and a high molecular type ultraviolet absorbent and a low molecular type HALS (hindered amine light stabilizer) and a high molecular type HALS as essential components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weather-resistant resin-coated metal sheet which does not use a vinyl chloride resin used for outdoor applications, for example.

[0002]

2. Description of the Related Art As a resin-coated metal sheet used for outdoor applications, a baking paint using a resin component having extremely good weather resistance such as a fluororesin is used, but a vinyl chloride-based resin coated metal sheet is also used. Widely used for exterior. This is because the vinyl chloride resin itself is a material having poor weather resistance, but has excellent compatibility with various additives, and has been studied for improvement of weather resistance for many years.
And although the absolute weather resistance is inferior to fluororesin, when comparing performance and cost, a vinyl chloride resin-coated metal plate can be said to be a very excellent exterior material.

However, in recent years, there has been a problem with heavy metals used as stabilizers for vinyl chloride resins, phthalic acid esters used as plasticizers have been suspected of having environmental hormonal effects, and hydrogen chloride gas has been incurred during combustion. The use of vinyl chloride resins has been limited due to environmental issues such as the generation of water and the generation of dioxins.

Therefore, there has been a demand for a resin-coated metal plate for exterior using a material other than the vinyl chloride resin. However, while it is becoming common to use polyolefin-based resins for interior applications, such resins cannot be used as is for exterior applications.

[0005] This is because polyolefin resins are generally poor materials having poor weather resistance, and have poor compatibility with various additives and weather resistance improvers. Due to the dissipation, the effect of the addition of the weathering agent is recognized, but the improvement effect proportional to the added amount cannot be obtained. The resin layer of the resin-coated metal plate has a thickness of about 0.5 mm even when it is thick, so that the problem of the polyolefin resin becomes more apparent.

[0006] In addition, when a pattern is printed to obtain a high design property, when a printed layer is provided on the surface of a colored polyolefin layer, the printed layer is directly exposed to ultraviolet light, so that it can be used in a short period of time. When printing is performed on the side of the transparent polyolefin resin that adheres to the base metal, causing discoloration, deterioration and dropout of the printed layer, in addition to the deterioration of the transparent polyolefin-based resin layer, peeling due to the deterioration of the adhesive layer The danger is higher than that of the polyolefin resin layer colored with the pigment.

[0007] On the other hand, even in the case of a conventional vinyl chloride resin-coated metal plate, a similar problem exists when an attempt is made to provide a printing layer. In order to improve this problem, a transparent material containing an ultraviolet absorber has been added. A method of coating an acrylic resin film on a printing layer has been adopted. That is, the ultraviolet absorber added to the acrylic film reduces ultraviolet deterioration of the printing layer and the vinyl chloride resin layer, and furthermore, the vinyl chloride resin layer does not need to be transparent, so that a large amount of inorganic pigment is added. This reduces the depth of penetration of ultraviolet light into the vinyl chloride resin layer, and furthermore, the adhesive interface with the base metal can be completely protected from ultraviolet light, so that a pattern printed product having relatively good weather resistance can be obtained. Can be

[0008] The transparent acrylic resin used for the surface coating can be firmly bonded to the vinyl chloride resin by heat fusion, and the binder resin used for the printing layer is an acrylic resin, a vinyl chloride resin or a blend resin thereof. In general, these adhesive interfaces have sufficient adhesive strength even after long-term exposure, and peeling occurs at the interface between the surface coating film and the vinyl chloride resin layer because the adhesive is mainly composed of resin. It is also an advantage of this configuration that there is little risk of doing this.

[0009] Accordingly, as for the polyolefin-based resin-coated metal plate, a printed product having a structure in which a transparent film to which an ultraviolet absorbent is added is similarly examined or put on the market. As the material of the transparent film, use the same or different types of polyolefin resin, polyester resin, fluorine resin, and acrylic resin similar to those used for coating with vinyl chloride resin. Have been.

Among these, when a transparent polyolefin resin is used, adhesive lamination by heat fusion is possible by using the same material as the polyolefin resin of the colored layer. Problems such as poor weather resistance of the resin itself and poor compatibility of the polyolefin-based resin with various weathering materials are problems, and it is not possible to provide sufficient weathering resistance so that the resin can be used as an exterior material. In addition to the problem of discoloration due to the deterioration of its own weather resistance, the polyester resin also has a problem that it cannot be thermally fused and laminated with the colored polyolefin layer.

When a transparent fluororesin film is used, the fluororesin itself has very good weather resistance, but also has poor compatibility with various weathering agents.
It is difficult to add a large amount of a weathering agent, and the protective effect of the printing layer and the colored polyolefin layer cannot be expected.Furthermore, since the fluororesin has poor adhesiveness, the fluororesin film peels off in a short period of exposure. It results in dropping.

On the other hand, when a film of a transparent acrylic resin is used, the acrylic resin has excellent weather resistance and has good compatibility with various weathering agents.
Since a relatively large amount of an ultraviolet absorber can be added, and the acrylic resin itself has relatively good weather resistance, a better protective effect can be obtained than each of the above transparent films.

Nevertheless, 25 to 150 actually used
At a thickness of about μm, the transmission of ultraviolet light cannot be completely blocked, and the vicinity of the acrylic film side surface of the colored polyolefin resin layer gradually undergoes ultraviolet deterioration with the progress of the exposure time, and sufficient weather resistance is not necessarily obtained. There was a problem that could not be obtained.

In this case, it is conceivable to further improve the weather resistance of the colored polyolefin-based resin layer itself, but this is also limited as described in the problem of the prior art, and a general weathering agent is forcibly used in a large amount. However, even if it is kneaded, it may appear as a blowout immediately after film formation, causing poor adhesion to the primer layer or print layer, and may even worsen the weather resistance.

Therefore, attempts have been made to increase the molecular weight of the ultraviolet absorber and the light stabilizer and to improve the compatibility with the polyolefin resin by introducing the structure of the polyolefin resin into a part of the molecular structure. I have. That is, a benzene ring of an ultraviolet absorber having a structure that is compatible with a polyolefin such as a relatively long-chain alkyl group or a so-called reactive ultraviolet light is added to a side chain of a polyolefin molecule having a molecular weight of about thousands to hundreds of thousands. Absorbents and reactive HALS are in the form of graft polymerization, and polyolefin resin molecules having molecular weights of thousands to hundreds of thousands are also reactive UV absorbers and reactive HALS with other reactive monomers such as methyl methacrylate. It is a form in which a copolymer is block-polymerized, or a form in which both a reactive ultraviolet absorber and a reactive HALS are copolymerized with another reactive monomer and block-polymerized with a polyolefin resin molecule.

HALS is a Hindered Amine Light
Stabirizer is an abbreviation for hindered piperidine-type light stabilizers, etc., and is generally used as a weather stabilizer because of its excellent radical scavenging ability in a temperature environment of 150 ° C. or lower, and is used as a polyolefin resin. Has been confirmed to be effective in preventing photo-oxidation degradation.

[0017]

However, high-molecular-weight ultraviolet absorbers and HALS having a portion compatible with the polyolefin resin are blown out immediately after film formation and exposed at the time of exposure compared to low-molecular-weight types. Of the surface over time is suppressed to a small extent, which means that the intended effect is obtained. However, since there are many parts in the molecule that do not participate in ultraviolet absorption or radial capture, the ultraviolet absorption efficiency or radial capture efficiency is poor, and the effect of improving weather resistance is almost expected when the same amount of low molecular weight weathering agent is added. Can not.

Therefore, in order to sufficiently improve the weather resistance with the above-mentioned polymeric weathering agent, a large amount of addition is required. However, in this case, there arise problems such as an increase in cost and a decrease in physical properties as a film.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to sufficiently and prolong the deterioration of a polyolefin-based resin-coated metal plate having a transparent resin film laminated thereon in place of a vinyl chloride-based resin due to ultraviolet rays. It is an object of the present invention to provide a weather-resistant resin-coated metal plate that can be suppressed over a wide range.

[0020]

In order to achieve the above object, according to the first aspect of the present invention, a colored polyolefin resin layer is provided on a base metal plate, and a transparent resin film is further laminated thereon. In the resin-coated metal plate having the above structure, both the low-molecular-weight ultraviolet absorber and the high-molecular-weight ultraviolet absorber, the low-molecular-weight HALS (hindered amine light stabilizer) and the polymer are contained in the colored polyolefin-based resin layer. And HALS of the type as an essential component, and an ultraviolet absorber in the transparent resin film.

Therefore, according to the present invention, the low molecular type ultraviolet absorber and HALS and the high molecular type ultraviolet absorber and HA
By containing LS in the colored polyolefin-based resin layer, the advantages of the low-molecular type and the high-molecular type are combined,
The weather resistance can be improved in a state where the amount of the weathering agent added as a whole is kept within a range where the physical properties of the film are not reduced. Further, the weather resistance of the transparent resin film is maintained by the ultraviolet absorber contained therein.

According to a second aspect of the present invention, in the first aspect of the present invention, the transparent resin film containing the ultraviolet absorber is obtained by grafting a (meth) acrylate-based resin monomer with a crosslinked elastic component as a core. The main component is a polymerized flexible (meth) acrylate resin.

Therefore, according to the present invention, since the acrylic resin has good compatibility with various weathering agents in addition to the good weathering resistance of the transparent resin itself, a relatively large amount of the weathering agent can be added. In addition, since the effect can be maintained for a relatively long time, the protective effect of the colored polyolefin layer and the adhesive interface can be maintained even after long-term exposure.

According to a third aspect of the present invention, in the first or second aspect, the high molecular weight ultraviolet absorber and the high molecular weight HALS have a molecular weight of 5,000 or more and a polyolefin resin. It is a block copolymer comprising a portion having a molecular structure and a portion having a form in which a reactive monomer having at least one of an ultraviolet absorbing group and a hindered piperidine structure is copolymerized with another reactive monomer.

Therefore, in the present invention, the compatibility between the polymer type ultraviolet absorber and the polymer type HALS and the colored polyolefin resin layer is improved by the presence of the portion having the molecular structure of the polyolefin resin. Therefore, even if the addition amount of the polymer type ultraviolet absorber and the polymer type HALS is increased as compared with the conventional case, the problem of blowing does not occur.
The deterioration of the physical properties of the colored polyolefin resin layer can be avoided.

According to a fourth aspect of the present invention, in the first aspect of the present invention, both resins are bonded between the colored polyolefin-based resin layer and the transparent resin film. An adhesive layer made of a resin having properties is provided.

Therefore, in the present invention, since the colored polyolefin-based resin layer and the transparent resin film are reliably laminated via the adhesive layer, the coloring polyolefin-based resin layer and the transparent resin film can be formed without considering mutual adhesion. The composition can be selected, and the degree of freedom increases. In addition, since the adhesive layer is a resin layer, a resin having an adhesive property is coextruded with a colored polyolefin resin or a transparent resin film, or a resin having an adhesive property is extruded into a film and heated.・ By applying pressure, the colored polyolefin resin layer, adhesive layer and transparent resin film can be easily laminated and integrated.

According to a fifth aspect of the present invention, in the fourth aspect, between the colored polyolefin-based resin layer and the adhesive layer or between the adhesive layer and the transparent resin film. A printing layer is provided. Therefore, in the present invention, the design is enhanced by the presence of the printing layer.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the adhesive layer also serves as a printing layer. Therefore, in the present invention, even if a solid printing layer is provided over the entire surface of the colored polyolefin resin layer as the printing layer, it is possible to avoid a decrease in the adhesiveness between the colored polyolefin resin layer and the transparent resin film.

[0030]

Embodiments of the present invention will be described below. FIG. 1A is a schematic sectional view showing a basic configuration of a weather-resistant resin-coated metal plate P of the present invention. The weather-resistant resin-coated metal plate P has a configuration in which a colored polyolefin-based resin layer 2 is laminated on one surface of a base metal plate 1, and a transparent resin film 3 to which an ultraviolet absorber is added is further laminated thereon. .

In the weather-resistant resin-coated metal sheet P shown in FIG. 1B, an adhesive layer 4 is provided between the base metal sheet 1 and the colored polyolefin-based resin layer 2, and FIG. The adhesive layer 5 is provided between the colored polyolefin-based resin layer 2 and the transparent resin film 3 in the weather-resistant resin-coated metal sheet P shown in FIG. Further, in the weather-resistant resin-coated metal plate P shown in FIG. 1D, a pattern printing layer 6 is further provided between the adhesive layer 5 and the transparent resin film 3.

As the base metal plate 1, a metal plate generally used as a base material of a resin-coated metal plate is used.
Specifically, hot-dip galvanized steel sheet, electro-galvanized steel sheet,
Examples include an aluminum / zinc composite plated steel sheet, an aluminum plated steel sheet, a stainless steel sheet, and an aluminum alloy sheet. There is no particular limitation on the thickness, heat treatment conditions, plating thickness, and the like of these metal plates, and the surface treatment of the metal plates may be performed by a phosphate treatment, a chromate treatment, or the like.

An adhesive layer 4 is provided between the base metal plate 1 and the colored polyolefin resin layer 2 as required.
Specifically, when the colored polyolefin-based resin layer 2 itself has a metal-adhesive composition, the adhesive layer 4 is not particularly required, but has a metal-adhesive property like a normal polyethylene-based resin or a polypropylene-based resin. If not, it is necessary to provide the adhesive layer 4.

The method for applying the adhesive layer 4 is to apply a liquid adhesive such as a solvent-based, dispersion-based, or emulsion-based adhesive, and then to dry the adhesive. Extruded multilayer film, base metal plate 1 and colored polyolefin resin layer 2
A method in which a hot-melt film or the like is sandwiched between layers during lamination, and a method in which the adhesive resin layer is formed by extruding and laminating an adhesive resin layer on a metal plate, and the like. However, the present invention is not limited to this. Further, the adhesive layer 4 may be a single layer or may be composed of a plurality of layers.

When a liquid adhesive is used, the adhesive that can be used is an acrylic adhesive, a urethane adhesive,
Acrylic / urethane adhesive, epoxy adhesive, phenol adhesive, amide adhesive, acid-modified olefin adhesive, vinyl acetate adhesive, polyester adhesive,
Copolyester-based adhesives, copolyamide-based adhesives and mixtures thereof. However, the adhesive is not limited to those exemplified above.

The method of applying the adhesive layer 4 using a liquid adhesive may be a method generally used for manufacturing a resin-coated metal plate. As an example, a method in which an adhesive dissolved in a solvent is continuously applied onto an unwound metal plate coil using a roll coater, and then introduced into a drying furnace installed in-line, and then into a baking oven. it can.

Further, both outer surfaces of the colored polyolefin resin layer 2 may be subjected to a surface treatment such as a corona discharge treatment or a chemical etching treatment in order to improve the adhesive strength.
As the colored polyolefin-based resin layer 2, a sheet generally used for resin-coated metal plates such as a polyethylene-based or polypropylene-based resin can be used as described above. In addition, those obtained by graft-polymerizing an organic acid anhydride (for example, maleic anhydride), those obtained by copolymerizing glycidyl methacrylate, and the like, or those obtained by blending a component imparting the adhesive, or olefins It is also possible to use those having flexibility imparted by containing a system elastomer component or a vinyl acetate component, and those blended with components imparting flexibility.

The thickness of the colored polyolefin resin layer 2 is as follows:
If it is thinner than this, the effect of hiding the base cannot be obtained unless a large amount of pigment is added, and the physical properties of the film may be reduced, and the absolute amount of the weathering agent that can be added is also reduced. Not preferred. Further, if the thickness is larger than this, the effect of improving the weather resistance is not improved, and the workability is lowered, which is not preferable.

The colored polyolefin resin layer 2 contains, as essential components, a low molecular weight UV absorber, a high molecular weight UV absorber, a low molecular weight HALS and a high molecular weight HALS.

As the low molecular weight ultraviolet absorber, a general one having a molecular weight of 200 to 700 can be used.
Various types such as benzotriazole type, benzophenone type and triazine type can be used. The preferable addition amount of the low-molecular-weight ultraviolet absorber is 0.1 to 1.0 part by weight with respect to 100 parts by weight of the polyolefin resin. The problem described above occurs, and there is a possibility that the adhesive force may decrease over time due to the transition to the bonding interface, which is not preferable. On the other hand, if the amount is less than this, most of the ultraviolet absorption depends on the high-molecular-weight ultraviolet absorber, and the same problem as in the case of adding only the high-molecular-weight ultraviolet absorber described in the problem of the prior art is caused. appear.

As the high molecular weight ultraviolet absorber, a structure compatible with polyolefin, such as a relatively long-chain alkyl group in the benzene ring of the ultraviolet absorber having a molecular weight of 1,000 or more, directly or through an ester bond or the like. The added one can be used, but one having a structure similar to the basic structural unit of the polyolefin-based resin constituting the colored polyolefin-based resin layer 2 in a part of the molecule is preferable from the viewpoint of compatibility. For example, a polymer obtained by graft-polymerizing a reactive UV-absorbing monomer to a side chain with the molecular structure of a polyolefin-based resin as a basic skeleton or an ultraviolet-absorbing monomer reactive with a portion having a molecular structure of a polyolefin-based resin may be used. A block copolymer comprising a reactive monomer and a portion having a copolymerized form can be preferably used. The molecular weight of the high-molecular-weight ultraviolet absorber is preferably 5000 or more. If the molecular weight is less than 5,000, it can be said that the compatibility is better than that of a low-molecular-weight type ultraviolet absorber, but it is not perfect and is not preferable for blowing over time. Although the upper limit of the molecular weight is not specified, if the molecular weight of the high-molecular-weight ultraviolet absorber is higher than the molecular weight of the olefin resin constituting the colored polyolefin resin layer 2, the fluidity at the time of film formation is affected. Therefore, there is a concern that the processability may be affected, and the molecular weight of the olefin-based resin is preferably equal to or less than that.

The preferred amount of the polymer type ultraviolet absorber is 0.1 to 100 parts by weight of the polyolefin resin.
If the amount is 5 to 5.0 parts by weight, and if the amount is more than this, the physical properties of the polyolefin-based resin layer film may be deteriorated. If the amount is less than 5 to 5.0 parts by weight, most of the ultraviolet absorption depends on the low-molecular ultraviolet absorber. And the same problem as the conventional weathering imparting compound occurs.

The low-molecular-weight HALS referred to in the present invention refers to those having a relatively low molecular weight as compared with the high-molecular-weight HALS of the present invention or those not satisfying the requirements of claim 3 of the present invention. , And the scope thereof is a concept including what is generally called “oligomer type” or “polymer type”.

As the low molecular weight HALS used in the present invention, those having a general structure having a molecular weight of 200 to 4000 can be used, and the preferable addition amount is 0 to 100 parts by weight of the polyolefin resin. 0.1 to 1.0 parts by weight. The problems that occur when the ratio is out of this range are the same as those in the case of the low-molecular ultraviolet absorber.

As the polymer type HALS, one having a structure similar to the basic constitutional unit of the polyolefin resin constituting the colored polyolefin resin layer 2 in a part of the molecule is preferable from the viewpoint of compatibility. The basic structure of the polymer type HALS is, for example, a polymer obtained by graft-polymerizing a reactive molecule having a hindered piperidine structure to a side chain with a molecular structure of a polyolefin resin as a basic skeleton, or having a molecular structure of a polyolefin resin. A block copolymer or the like comprising a portion and a portion having a form in which a reactive monomer having a hindered piperidine structure in a molecule is copolymerized with another reactive monomer can be preferably used. The polymer type H
The molecular weight of ALS is also preferably 5000 or more, for the same reason as in the case of the polymeric UV absorber.

The preferable addition amount of the polymer type HALS is 0.5 to 100 parts by weight of the polyolefin resin.
At 5.0 parts by weight, if the amount is more than this, the physical properties of the polyolefin-based resin layer film may be deteriorated,
If the amount is less than this, most of the light other than the ultraviolet light, particularly the visible light absorption, depends on the low molecular weight HALS, and the same problem as the conventional weathering-imparting compound occurs.

Further, the polymer type ultraviolet absorber and the polymer type HALS may have both an ultraviolet absorbing group and a hindered piperidine structure in the same molecule. As an example, a form in which both a portion having a molecular structure of a polyolefin resin, a UV-absorbing monomer having a reactivity, and a reactive monomer having a hindered piperidine structure in a molecule are copolymerized with another reactive monomer. And a block copolymer composed of moieties.

The colored polyolefin resin layer 2 is colored by adding a pigment. As for pigments,
Since the penetration depth of the ultraviolet ray changes depending on the type and the amount added, the influence on the weather resistance is large. For the purpose of protecting the adhesive layer 4 from ultraviolet rays and suppressing the deterioration of the colored polyolefin-based resin layer 2 itself due to ultraviolet rays to a deep portion, a titanium oxide-based pigment is used as an extender with respect to 100 parts by weight of the polyolefin-based resin. It is preferably added in an amount of 12 to 18 parts by weight, and a desired hue (color tone) is adjusted by further adding a coloring pigment. Even when the print layer 6 is provided, when the color of the print layer 6 is compensated for, the print layer 6 is partially provided, and it is necessary to secure the design property of the unprinted portion. In some cases, a coloring pigment is added to adjust the color of the colored polyolefin-based resin layer 2.

In the colored polyolefin-based resin layer 2, in addition to the above components, a process stabilizer generally added to the polyolefin-based resin, an antioxidant such as a phenolic / phosphorous type, a metal catalyst inactivating agent, A catalyst adsorbent, a flame retardant, and other fillers may be added.

As the transparent resin film 3 containing an ultraviolet absorber, a film having good weather resistance such as a fluororesin film or an acrylic resin film can be used.
In addition, a film mainly composed of a layer made of an acrylic resin having excellent compatibility with various weathering agents is particularly preferable.
The transparent acrylic resin film is an acrylic film containing a crosslinked acrylic rubber, and is generally called “soft acrylic”, “flexible acrylic”, “film grade acrylic” or the like. This acrylic film is harder to bend and whiten than ordinary acrylic resin and impact-resistant acrylic, and has a tensile elongation at break of 50% or more, so that it can be bent to some extent even after being laminated as a surface coating layer. And used for coating the surface of a vinyl chloride resin-coated steel sheet or the like. As the transparent acrylic resin film, a film to which various commercially available ultraviolet absorbers are added can be suitably used.

The thickness of the transparent resin film 3 is 20 to 15
It is preferable to select in the range of 0 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 to be bonded and laminated = the surface on the outside air side) may be provided with further weather resistance, stain resistance, chemical resistance, etc. For the purpose, a resin layer provided with another resin layer or a film blended with another resin having compatibility with the acrylic resin can also be considered to be included in the category of the acrylic resin film. It can be suitably used.

When the colored polyolefin-based resin layer 2 does not have a heat-sealing property with the transparent resin film 3, an adhesive layer 5 is required for laminating them. The adhesive layer 5 may be the same material as or different from the adhesive layer 4 when the colored polyolefin-based resin layer 2 and the base metal plate 1 are bonded and laminated. However, unlike the adhesive layer 4, the adhesive layer 5 is in a state of being protected from ultraviolet rays only by the ultraviolet absorbent added to the transparent resin film 3. In the preferred thickness of the transparent resin film 3, it is difficult to completely block the transmission of ultraviolet rays over a long period of time even if a large amount of an ultraviolet absorber is added. It is preferable to use a coating layer made of a modified acrylic resin. Examples of the coating agent having the composition include "Polyment NK-380" (manufactured by Nippon Shokubai Co., Ltd.), but are not limited thereto. Further, the method of applying the adhesive layer 5 is not limited to the coating of the liquid material, and various methods can be employed as in the case of the adhesive layer 4.

The weather-resistant resin-coated metal plate P is provided between the colored polyolefin-based resin layer 2 and the adhesive layer 5 or between the adhesive layer 5 and the transparent resin film 3, such as stones, wood grain, and abstract patterns. A printing layer 6 may be provided. The printing layer 6 can be applied by various known methods. For example, an acrylic resin film is used as the transparent resin film 3, and a printing layer using an acrylic binder on the laminated surface side of the film is used as an example. 6 on the other hand, the adhesive layer 5 is provided on the surface of the colored polyolefin-based resin layer 2 by applying “Polyment NK-380”, and these are laminated and integrated by heat fusion to form a laminate with a print layer. A method for obtaining a film can be mentioned. However, the method is not limited to this method.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. Each sample used in Examples 1 and 2 and Comparative Examples 1 to 5 was prepared by the following procedure.

(A) A transparent resin film containing an ultraviolet absorber: a commercially available UV-cut acrylic resin film HBS-
006 (manufactured by Mitsubishi Rayon Co., Ltd.) was used as it was.

(B) Colored polyolefin resin film: (hereinafter sometimes referred to as PE layer) Low density polyethylene (LDPE): LF-320H (Nippon Polychem Co., Ltd.)
70 parts by weight, high-density polyethylene (HDPE): H
Y-331 (manufactured by Nippon Polychem Co., Ltd.) containing 30 parts by weight of a resin component, an antioxidant: ADK STAB AO-50
0.3 parts by weight (manufactured by Asahi Denka Co., Ltd.), extender pigment: 15 parts by weight of titanium oxide, and the type and amount (parts by weight) of an ultraviolet absorber and HALS shown in Table 1 according to Examples and Comparative Examples are added.

[0058]

[Table 1] In addition, the structure and physical properties of the weathering agent of the product name in Table 1 are as follows.

Adeka 1413: a benzophenone-based ultraviolet absorber manufactured by Asahi Denka Kogyo KK, molecular weight: 326, melting point: 48 ° C.

[0060]

Embedded image Adeka LA-51: manufactured by Asahi Denka Kogyo Co., Ltd., benzophenone-based ultraviolet absorber, molecular weight: 468, melting point: 225 ° C.

[0061]

Embedded image Chimasorb 944LD: HALS manufactured by Ciba Specialty Chemicals Co., Ltd. Molecular weight: 2000-3100, melting point: 100-135 ° C

[0062]

Embedded image Kuraray X-3907: high molecular type UVA + HALS, molecular weight: about 10,000 (k + m + n): j ≒ 1: 1 (weight ratio) k: m = 1: 1 (molar ratio)

[0063]

Embedded image The resin pellets and the additive were respectively supplied to one twin-screw kneading extruder using two quantitative feeders, extruded from a strand die, and then cut by a pelletizer installed in-line, A polyethylene pellet into which the additive component was kneaded was formed.
The mixture was put into a single-screw extruder having a thickness of 100 mm and extruded from a T-die to obtain a colored polyolefin resin film having a thickness of 100 μm.

(C) Application of Adhesive Layer 4 and Adhesive Layer 5 Both surfaces of the colored polyolefin resin film are subjected to corona discharge treatment (discharge energy: 50 w · min / m ² ).
And then apply a modified acrylic resin-based coating agent “Polyment NK-380” (manufactured by Nippon Shokubai Co., Ltd.) to both sides sequentially with a bar coater to a dry thickness of 2.0 μm, and hold the film so as not to shrink Then, the mixture was put into a hot air oven and dried at 105 ° C. for 2 minutes.

(D) Lamination of transparent resin film 3 and colored polyolefin resin film provided with an adhesive layer These two films were laminated between a metal roll heated to 120 ° C. and a release roll. And heat-sealed to form a laminated film. Since the adhesive layers 4 and 5 were provided on both sides of the colored polyolefin-based resin film, lamination and integration were performed with the heated metal roll side as the acrylic resin film and the release roll side as the polyethylene resin film. Was.

(E) Preparation of resin-coated metal plate A polyester-based adhesive was applied to one side of a hot-dip galvanized steel plate having a thickness of 450 μm and surface-treated with phosphoric acid so as to have a thickness of 5 μm after drying. Simultaneously, the laminated resin film was laminated on the adhesive layer of the steel plate to obtain a resin-coated metal plate.

Each of the resin-coated metal plates of Examples and Comparative Examples was
The sample for evaluation was cut into a size of 0 mm × 50 mm. The end face of the cut portion was not particularly treated. These samples were subjected to accelerated exposure evaluation (black panel temperature = 63 ° C.) using Sunshine Weather Meter (manufactured by Suga Test Instruments Co., Ltd.), and exposure was performed for 2,000 hr, 3,000 hr,
The following items were evaluated for the test pieces after 4000 hr and 6000 hr, and compared with the test pieces before exposure.

<Cutting force of polyolefin layer>
The average cutting force from the surface side of the colored polyolefin-based resin layer 2 to the depth of 20 μm to 50 μm was determined by the surface / interface property analyzer “CYCUS” of Wintes Co., Ltd., and was not exposed to the sunshine weather meter. The state of deterioration of the polyolefin resin layer was evaluated by relative comparison with the sample.

Here, the measurement principle of the surface / interface property analyzer “CYCUS” will be described with reference to FIGS. 2 (a) to 2 (c) and FIGS. 3 (a) and 3 (a).
This will be briefly described according to (b). "Cycus" uses a sharp cutting edge to continuously cut from the surface of the resin coating layer to the interface, and the "cutting theory"
Is applied to determine the material shear strength and the interfacial adhesion strength from the force during interfacial cutting.

As shown in FIGS. 2A to 2C, the measuring mechanism is a cutting blade 1 which moves simultaneously in the horizontal and vertical directions.
The horizontal component Fh and the vertical component Fv when the sample 1 enters the measurement material 12 are measured by a detector, and the measured data is taken into a personal computer to analyze the data. The cutting blade feed mechanism 13 can set the horizontal feed speed and the vertical feed speed in several steps, and in the vertical direction, push the cutting blade 11 with a constant load in addition to the speed control (load control mode).
Is also possible.

The measurement of the material shear strength is performed by moving the cutting blade 11 obliquely at a predetermined angle as shown in FIG. 2B from the measurement start state in FIG. The measurement time is measured, and the relationship between the depth of cut and the cutting force is obtained from a graph as shown in FIG. Then, the material shear strength λ (kgf / cm ² ) is obtained from the following equation.

Λ = Fc / (2 · d · H · cotφ) where Fc: cutting force, d: depth of cut, H: width of cutting edge, φ: shear angle The above calculation based on the theory of “Merchant” Although it is possible to obtain the material shear strength λ from the equation, in the evaluation of the present invention, a method of comparing the cutting forces was adopted.

As shown in FIG. 2C, when the cutting blade 11 reaches the interface between the upper layer 12a and the lower layer 12b, the feed in the vertical direction is set to zero (cut limiting function). The cutting force at the interface is measured by moving the cutting blade 11 horizontally.

Then, from the following equation, the interface adhesive force k (kgf /
cm = N / cm). k = Fc / H, where Fc: cutting force, H: width of the cutting blade <base adhesive force> A cut is made from the surface of the resin-coated metal plate on the resin-coated side to reach the metal plate surface with the blade of a cutter knife. At the same time, when the blade of the cutter knife is twisted and the resin coating is turned up, when the resin coating floats and peels off from the metal plate, it is marked as "x", and when it does not occur, it is marked as "o" evaluated. Further, those in which spontaneous peeling occurred on the end face of the exposed sample were also evaluated as “×”.
“△” indicates that peeling occurred in some of the plurality of samples.

Evaluation Results <Cutting Force of Polyolefin Layer> The measurement results are shown in Table 2 and FIGS. The cutting force is represented by N (Newton).

[0076]

[Table 2] In Comparative Example 1 in which the weathering agent was not added, the cutting force of the PE layer was already significantly reduced after 2,000 hours of exposure, and deterioration of the PE layer could not be suppressed only by coating the transparent acrylic film containing the ultraviolet absorbent. You can see that. Exposure 2000
In the time sample, when the laminated film was to be peeled off from the metal plate, the PE layer was in a state of being collapsed into a powdery state.

In Examples 1 and 2, the change in the cutting force of the PE layer with time is small, and the deterioration is effectively suppressed. In Comparative Examples 2 and 3 in which only the general type UVA and HALS were added, the change in the cutting force with time was small at the time of exposure of 4000 hours, but a decrease was observed at the time of exposure of 6000 hours, and no weathering agent was added (Comparative Example). Compared to 1), it can be said that the weather resistance is much better, but it does not reach the level of the examples.

Further, compared with the embodiment, the polymer type UVA.H
In Comparative Example 4 in which the amount of ALS added was small, the results were not significantly different from those in Comparative Examples 2 and 3, and it is considered that the effect was not obtained due to the small amount of ALS.

In Comparative Example 5 in which only the polymer type UVA / HALS was added, a decrease in the cutting force was observed after 6000 hours of exposure. <Interfacial Adhesive Force> The measurement results are shown in Table 3 and FIGS. The adhesion is expressed in N / cm.

[0080]

[Table 3] Comparative Example 1 without the addition of the weathering agent showed a low value at the time of exposure of 2,000 hours.
This is due to the deterioration and collapse of the E layer.

In Comparative Examples 2, 3, and 4, the adhesive strength was also low after exposure for 2000 hours.
At this point, since no deterioration of the PE layer was observed, it is considered that the adhesion at the interface was purely lowered. After 3000 hours of exposure, the decrease in adhesion becomes even more pronounced.

In Comparative Example 5, no decrease in interfacial adhesion was observed until 4000 hours of exposure, but a decrease was observed after 6000 hours. In contrast, in Examples 1 and 2 of the present invention, no decrease in interfacial adhesion was observed even after exposure for 6000 hours.

<Adhesive Strength to Base Metal Plate (Base Adhesive Strength)> Table 4 shows the measurement results.

[0084]

[Table 4] “Cycus” reflects the physical properties of the layer above the interface that one wants to observe in the measurement method. Regarding the interfacial adhesive force between the transparent acrylic layer and the PE layer and the cutting force of the PE layer, the measured value of "CYCUS" was used because the physical properties of the transparent acrylic layer did not change significantly after about 6000 hours of exposure. Regarding the adhesive strength with the metal plate,
Since the degradation state of the PE layer was significantly different up to 6000 hours of exposure, the simple meaning of peeling off with a cutter knife was employed to avoid making the numerical significance unclear.

In Comparative Example 1, it was difficult to determine the adhesive strength due to deterioration and collapse of the PE layer, but in Comparative Examples 2 to 5, no decrease in the adhesive strength of the substrate was observed until 6000 hours of exposure. However, after 6000 hours of exposure, 0.5 to 1.0 mm from the end of the sample was turned up by natural peeling.

On the other hand, in Examples 1 and 2, even when exposure was performed for 6000 hours, sufficient adhesive strength was obtained, and no curling of the edge occurred. This embodiment has the following effects.

(1) Low molecular ultraviolet absorber and HA
Since the LS, the high molecular type ultraviolet absorber and the HALS are contained in the colored polyolefin resin layer 2, the advantages of the low molecular type and the high molecular type are combined, and the addition of the weathering agent as a whole The weather resistance can be improved in a state where the amount is kept within a range where the physical properties of the film are not reduced. Further, the transparent resin film 3 also maintains weather resistance due to the ultraviolet absorber contained therein.

(2) The transparent resin film 3 is mainly composed of a flexible (meth) acrylate-based resin obtained by graft polymerization of a (meth) acrylate-based resin monomer with a crosslinked elastic component as a core. Therefore, in addition to the good weather resistance of the transparent resin itself, the acrylic resin has good compatibility with various weathering agents, so that a relatively large amount of a weathering agent can be added, and the effect is relatively small. Since it can be maintained for a long time, the protective effect of the colored polyolefin layer and the adhesive interface can be maintained even after the long-term exposure.

(3) A high molecular weight ultraviolet absorber and a high molecular weight HALS are provided with a portion having a molecular structure of a polyolefin resin and have a molecular weight of 5000 or more. Therefore, in the present invention, since the presence of the portion having the molecular structure of the polyolefin-based resin and the molecular weight have an appropriate size, the compatibility with the colored polyolefin-based resin layer 2 is improved, and the polymer-type ultraviolet ray is used. Even if the amounts of the absorbent and the polymer type HALS are increased as compared with the conventional case, it is possible to avoid a decrease in the physical properties of the colored polyolefin-based resin layer 2.

(4) The polymer type ultraviolet absorber and the polymer type HALS have a molecular weight of 5,000 or more and a portion having a molecular structure of a polyolefin resin and a reactive monomer having an ultraviolet absorbing group are subjected to another reaction. It is composed of a block copolymer composed of a portion having a form copolymerized with a reactive monomer and a portion having a form in which a reactive monomer having a hindered piperidine structure is copolymerized with another reactive monomer. Therefore, a polymer type ultraviolet absorber and a polymer type HALS
Are separately formed and mixed with the colored polyolefin-based resin layer 2, whereby it becomes easier to uniformly disperse the polymer type ultraviolet absorber and HALS in the colored polyolefin-based resin layer 2. And the weather resistance is further improved.

(5) Colored polyolefin resin layer 2
An adhesive layer 5 made of a resin having an adhesive property with both the resin and the transparent resin film 3 is provided. Therefore, since the colored polyolefin-based resin layer 2 and the transparent resin film 3 are reliably laminated via the adhesive layer 5, the composition of the colored polyolefin-based resin layer 2 and the transparent resin film 3 can be determined without considering the mutual adhesiveness. Can be selected, and the degree of freedom increases. Since the adhesive layer 5 is a resin layer, a state in which a resin having adhesive properties is coextruded with the colored polyolefin resin or the transparent resin film 3 or a resin having adhesive properties is extruded into a film state is superposed. By heating and pressurizing, the colored polyolefin-based resin layer 2, the adhesive layer 5, and the transparent resin film 3 can be easily laminated and integrated.

(6) Adhesive layer 5 and transparent resin film 3
Since the print layer 6 is provided between the first and second layers, the design property is enhanced by the presence of the print layer 6. The embodiment is not limited to the above, and may be embodied as follows, for example.

The printed layer 6 is replaced between the adhesive layer 5 and the transparent resin film 3 and the colored polyolefin resin layer 2
And the adhesive layer 5 may be provided. Also in this case, the design property is enhanced by the presence of the printing layer 6.

In place of providing the printing layer 6 independently of the adhesive layer 5, the adhesive layer 5 may also serve as the printing layer 6. In this case, even if a solid print layer 6 covering the entire surface of the colored polyolefin-based resin layer 2 is provided as the print layer 6, the colored polyolefin-based resin layer 2 and the transparent resin film 3
Can be prevented from lowering the adhesiveness.

The transparent resin film 3 may be formed of a normal acrylic resin or an impact-resistant acrylic resin in place of the acrylic film containing a crosslinked acrylic rubber component. In this case, bending after lamination is difficult, but since it has excellent compatibility with various weathering agents, the protective effect of the colored polyolefin layer and the adhesive interface can be maintained even after long-term exposure.

In place of the constitution in which the polymer type ultraviolet absorber and the polymer type HALS are contained in the same polymer as the block copolymer component, the polymer UV absorber and the polymer type HALS may be contained in different polymers as the block copolymer component. Good. In this case, although the uniformity of the concentration is inferior to that obtained by block copolymerization in the same polymer, the degree of freedom of the addition ratio is increased, and the adjustment of the weather resistance level and the cost adjustment become easy.

The technical ideas (inventions) other than those described in the claims that can be grasped from the above embodiment will be described below. (1) In the invention according to claim 3, the high-molecular-weight ultraviolet absorber and the high-molecular-weight HALS include a polyolefin-based resin having a molecular structure and a reactive monomer having an ultraviolet-absorbing group. And a block copolymer composed of a portion having a form copolymerized with a reactive monomer having a hindered piperidine structure and a portion having a form copolymerizing a reactive monomer having a hindered piperidine structure with another reactive monomer.

[0098]

As described in detail above, claims 1 to 6 are provided.
In the invention described in (1), deterioration of a polyolefin-based resin-coated metal plate on which a transparent resin film is laminated in place of a vinyl chloride-based resin can be sufficiently and for a long time suppressed.
As a result, by not using vinyl chloride resin, it is free from various environmental problems, and exhibits superior weather resistance compared to conventional resin-coated metal plates mainly based on polyolefin resin films, Life cycle is extended, which leads to reduction of environmental load. Moreover, it can be suitably used when it has a pattern printing layer.

[Brief description of the drawings]

FIGS. 1A to 1D are schematic cross-sectional views showing the configuration of a weather-resistant resin-coated metal plate embodying the present invention.

FIG. 2 is a schematic view showing cutting of a circus.

FIGS. 3A and 3B are graphs for obtaining a cutting force by using a circus.

FIG. 4 is a graph showing a change in cutting force according to the exposure time of the example.

FIG. 5 is a graph showing a change in cutting force according to exposure time in a comparative example.

FIG. 6 is a graph showing a change in interfacial adhesive force according to the exposure time in Examples.

FIG. 7 is a graph showing a change in interfacial adhesive force according to the exposure time of a comparative example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base metal plate, 2 ... Colored polyolefin resin layer, 3
... Transparent resin film, 4,5 ... Adhesive layer, 6 ... Print layer,
P: Weather-resistant resin-coated metal plate.

 ──────────────────────────────────────────────────の Continued on the front page F-term (reference) 4F100 AB01A AH03H AK01C AK01H AK01J AK03B AK25C AK25J AL02H AL04C AL09C BA03 BA10A BA10C BA13 CA07B CA07C EJ05C HB00B HB31 JA06H JK13C JL00 JL01 JL00 JL09

Claims (6)

[Claims] 1. A resin-coated metal plate having a structure in which a colored polyolefin-based resin layer (2) is provided on a base metal plate (1), and a transparent resin film (3) is further laminated thereon. Both the low molecular weight UV absorber and the high molecular weight UV absorber, the low molecular weight HALS (hindered amine light stabilizer) and the high molecular weight HALS are contained in the resin layer (2) as essential components. A weather-resistant resin-coated metal plate comprising an ultraviolet absorber in the transparent resin film (3). 2. A flexible (meth) acrylate-based resin in which a transparent resin film (3) containing the ultraviolet absorber is graft-polymerized with a (meth) acrylate-based resin monomer using a crosslinked elastic component as a core. The weather-resistant resin-coated metal plate according to claim 1, comprising: 3. The high-molecular-weight ultraviolet absorber and the high-molecular-weight HALS have a molecular weight of 5,000 or more and have a molecular structure of a polyolefin resin and at least one of an ultraviolet-absorbing group and a hindered piperidine structure. The weather-resistant resin-coated metal sheet according to claim 1 or 2, wherein the block is a block copolymer comprising a reactive monomer having a form copolymerized with another reactive monomer. 4. The colored polyolefin resin layer (2)
The weather resistance according to any one of claims 1 to 3, wherein an adhesive layer (5) made of a resin having an adhesive property with both the resin and the transparent resin film (3) is provided. Resin coated metal plate. 5. The colored polyolefin-based resin layer (2).
And the adhesive layer (5) or the adhesive layer (5)
The weather-resistant resin-coated metal plate according to claim 4, wherein a printing layer (6) is provided between the metal layer and the transparent resin film (3). 6. The weather-resistant resin-coated metal sheet according to claim 5, wherein the adhesive layer (5) also serves as a printing layer (6).