JPH1191025A - Overlay film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extremely improve the weatherability of an overlay film, and also improve the transparency, antiblocking property, and abrasion resistivity thereof by forming a surface layer being H or more in pencil hardness and having weatherability on at least one surface of a thermoplastic film. SOLUTION: A surface hardness layer being H or more in pencil hardness and having weatherability is formed on at least one surface of a thermoplastic film. A polyester film is most suitable for such a thermoplastic film in terms of mechanical strength, dimensional stability, transparency, or the like. The surface hardness layer being H or more in pencil hardness and having weatherability can be formed, e.g. with benzotriazole-based monomer copolymeric acryl resin or the like. The resin is obtained by a copolymerization of bezotriazole-based monomer and acrylic monomer. The benzotriazole-based reactive monomer is preferably is 2-(2,-hydrox 5,-methacryloxyethylphenyl)-2H- benzotriazole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overlay film, and more particularly to an overlay film having excellent weather resistance, transparency, blocking resistance and scratch resistance.

[0002]

2. Description of the Related Art Heretofore, as an overlay film, a so-called pet composed of a steel plate / vinyl chloride (PVC) film or a sheet / polyethylene terephthalate film (PET) has been used as an outer frame of a refrigerator or a wall material of a unit bath. -There is a PVC steel sheet, and as the PET film, a normal film not considering the weather resistance and the scratch resistance is used.

[0003]

However, the above-mentioned prior art has the following problems.

That is, in recent years, openings in houses (light-shielding properties,
(Comfort) has increased in size, so sunlight (ultraviolet rays) incident on the interior has increased, and the deterioration of the surface has been accelerated. It is insufficient in weather resistance.
Further, in a normal PET film, since the hardness of the surface is low, there is a problem in that the transparency and aesthetic appearance are deteriorated due to scratches on the surface caused by daily cleaning or the like.

[0005] Further, as a laminate having a scratch resistance, a laminate in which a cured layer of a radiation-curable composition is provided on a PET film which has been treated with a primer (JP-A-60-166453).
However, it is impossible to prevent the weather resistance of the base film from deteriorating.

An object of the present invention is to improve the above-mentioned drawbacks, that is, to provide an overlay film having extremely excellent weather resistance and excellent transparency, blocking resistance and scratch resistance.

[0007]

According to the present invention, there is provided an overlay film characterized in that a thermoplastic film has a surface layer having a pencil hardness of H or more and a weather resistance on at least one side thereof. is there.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The term "thermoplastic film" as used in the present invention is a general term for a film which is melted or softened by heat.
Although not particularly limited, typical examples include polyester films, polypropylene, polyolefin films such as polyethylene, polyaramid films represented by nylon, polyvinyl chloride films,
A polycarbonate film, an acrylic film, a fluorine film, or the like can be used. Among them, a polyester film is preferred from the viewpoint of mechanical strength, dimensional stability, transparency and the like.

The term "polyester film" is a generic term for a polymer film having an ester bond as a main bonding chain. Particularly preferred polyester films include polyethylene terephthalate film and polyethylene-based film.
2,6 naphthalate film, polybutylene terephthalate film, polybutylene-2,6 naphthalate film and the like can be used. Among them, polyethylene terephthalate film, polyethylene-2,6 naphthalate are preferable in terms of quality and economy. Film is most preferred. The thickness of the polyester film is not particularly limited, but is preferably in the range of 25 to 250 μm. 25-50 especially when used for steel plate overlay
The range of μm is preferred.

In the present invention, it is necessary that at least one surface of the thermoplastic film has a surface hardness layer having a pencil hardness of H or more and weather resistance.

The surface hardness layer having a pencil hardness of H or more and having weather resistance can be made of, for example, a benzotriazole monomer copolymerized acrylic resin. The resin is a resin obtained by copolymerization of a benzotriazole-based reactive monomer and an acrylic monomer, and the obtained polymer is in any form such as an organic solvent-soluble one or a water-dispersible one. Is also good. The benzotriazole-based reactive monomer may be any monomer having benzotriazole in the base skeleton and having an unsaturated double bond, and is not particularly limited.
-(2, -Hydroxy-5, -methacryloxyethylphenyl) -2H-benzotriazole is preferred. Examples of the acrylic monomer copolymerized with this monomer include alkyl acrylate and alkyl methacrylate (the alkyl group is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group,
A monomer having a crosslinkable functional group, such as a carboxyl group, a methylol group, an acid anhydride group, a sulfonic acid group, an amide group, or a methylolated amide, such as a 2-ethylhexyl group, a lauryl group, a stearyl group, or a cyclohexyl group. A monomer having a group, an amino group (including a substituted amino group), an alkylolated amino group, a hydroxyl group, an epoxy group, or the like can be used. Examples of the monomer having the above functional group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, vinylsulfonic acid, styrenesulfonic acid, acrylamide, methacrylamide, N-methylmethacrylamide, and methylolated acrylamide. , Methylolated methacrylamide, diethylaminoethyl vinyl ether, 2-aminoethyl vinyl ether, 3-aminopropyl vinyl ether, 2-aminobutyl vinyl ether, dimethylaminoethyl methacrylate, and those in which the above amino group is methylolated, β-hydroxyethyl acrylate,
β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, β-hydroxy vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, glycidyl acrylate, glycidyl methacrylate Etc. can be used, but it is not necessarily limited to this. In addition to the above, the following monomers, for example, acrylonitrile, methacrylonitrile, styrene, butyl vinyl ether, mono or dialkyl esters of maleic acid and itaconic acid, methyl vinyl ketone, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl pyridine, Vinylpyrrolidone, alkoxysilane having a vinyl group, polyester having an unsaturated bond, or the like may be used as the copolymerization component.

When the above-mentioned acrylic monomer is used, one or more of the above-mentioned acrylic monomers may be copolymerized in an arbitrary ratio. Preferably, methyl methacrylate or styrene is used in an amount of at least 50% by weight of the acrylic monomer. More preferably, 70% by weight or more is copolymerized in view of the hardness of the laminated film. The copolymerization ratio of the benzotriazole monomer and the acrylic monomer is such that the ratio of the benzotriazole monomer is 10% by weight to 70% by weight, preferably 20% by weight to 65% by weight, more preferably 25% by weight to 60% by weight. % Or less,
It is preferable in terms of weather resistance, adhesion to the base film, and durability. The molecular weight of the present copolymer is not particularly limited, but is preferably 5,000 or more, more preferably 10,000 or more, from the viewpoint of the durability of the laminated film. The production of the present copolymer can be obtained by a method such as radical polymerization, and is not particularly limited. In the present invention, the above-mentioned copolymer is laminated on a base film as an organic solvent or an aqueous dispersion.
A range of 0 μm, preferably 0.6 to 7 μm, and more preferably 0.8 to 7 μm is desirable in terms of weather resistance, flexibility and the like.

The overlay film according to the present invention comprises, on a thermoplastic film, an (A) layer mainly composed of a benzotriazole monomer copolymerized acrylic resin, and a benzotriazole-based reactive layer on the (A) layer. Surface hardening layer containing an ultraviolet absorber and having a pencil hardness of H or more (B)
Can also be preferably realized by a structure in which are laminated.

In such a structure, it is preferable not to add fine particles or the like in order to improve the transparency of the laminated film in the layer (A). Particles may be added. The fine particles to be added are not particularly limited, and inorganic particles,
It can be selected from organic particles and the like. As the inorganic particles, calcium carbonate, silica, alumina and the like can be used, and as the organic particles, particles such as acryl, polyester, cross-linked acryl and silicone can be used.

Further, urea resin, melamine resin, alkyd resin, polyester resin, urethane resin, silicon resin and the like may be added in order to improve the adhesion between the substrate film and the surface hardening layer (B). . In particular, the addition of a melamine resin is preferable since the effect of improving the adhesion to the substrate film and the surface hardness layer is large.

The layer made of the above-mentioned benzotriazole-based monomer copolymerized acrylic resin can be provided by various methods. For example, a method such as a roll coating method, a gravure coating method, a reverse coating method, and a rod coating method can be used on a biaxially oriented polyester film. Also, applied to the surface of the base polyester film before the completion of the crystal orientation using any of the above methods,
After drying, a method of extending in at least one axis direction to complete the crystal orientation is also preferably used.

Various methods can be used for the base film in order to improve the adhesion to the laminated film. That is, any method such as corona discharge treatment, plasma treatment, fire treatment, or anchor treatment with polyester resin, acrylic resin, urethane resin, polyvinyl chloride resin, or the like in an atmosphere such as air, nitrogen, or carbon dioxide can be used. it can. As the above-mentioned surface hardening layer (B) layer, a layer made of acrylic, urethane, melamine, organic silicate, silicone, metal oxide, or the like can be used. In particular, silicones and acrylics are preferable in terms of hardness and durability, and acrylics are more preferable when curability, flexibility and productivity are taken into consideration, and active ray curing is most preferable. Acrylic type.

The actinic ray-curable acrylic system contains an acrylic oligomer and a reactive diluent as actinic ray polymerization components, and further contains, if necessary, a photoinitiator, a photosensitizer, and a modifier. Is also good.

As the acrylic oligomer, those in which a reactive acrylic group is bonded to an acrylic resin skeleton, polyester acrylic, urethane acrylic, epoxy acrylic,
Polyether acryl or the like can be used, and a rigid skeleton such as melamine or isocyanuric acid to which an acrylic group is bonded can also be used, but it is not limited thereto.

The reactive diluent is used as a medium of the coating agent, that is, a solvent for the coating process, and has a group which itself reacts with a monofunctional or polyfunctional acrylic oligomer. What becomes a polymerization component can be used.

In particular, in the case of crosslinking by ultraviolet rays, since the light energy is small, it is preferable to add a photopolymerization initiator and / or a sensitizer to promote the conversion and initiation of the light energy.

Specific examples of the above-mentioned acrylic oligomer, reactive diluent, photopolymerization initiator, sensitizer, crosslinking device, etc.
Shinzo Yamashita and Tosuke Kaneko, "Handbook of Crosslinking Agents", Taiseisha 1980, pp. 267-275, 56
Pages 2 to 593 can be referenced, but are not limited thereto. In addition, products such as Mitsubishi Rayon Co., Ltd., Fujikura Kasei Co., Ltd., Dainichi Seika Co., Ltd., Dainippon Ink and Chemicals Co., Ltd., and Toa Gosei Co., Ltd. However, the present invention is not limited to these.

As the modifier for the surface hardening layer (B) layer,
As long as the reaction by actinic radiation is not impaired, a coatability improver, defoamer, thickener, antistatic agent, inorganic particles, organic particles, organic lubricant, dye, pigment, stabilizer, etc. It can be used, and the characteristics of the surface hardened layer can be improved depending on the application. When the surface hardening layer is provided, an organic solvent may be added for the purpose of improving workability at the time of coating and controlling the coating film thickness within a range that does not impair the effects of the present invention.

In the present invention, the surface hardening layer is
At least one monomer having three or more (meth) acryloyloxy groups in one molecule and at least one monomer having one to two ethylenically unsaturated double bonds in one molecule; An actinic ray-curable product containing an actinic ray-curable monomer composition as a main component can be used. This is excellent in hardness, curability, scratch resistance,
It is preferable because it has excellent flexibility.

In the present invention, three or more (meth) acryloyloxy groups in one molecule (here, (meth)
The acryloyloxy group is an abbreviation of an acryloyloxy group and a methacryloyloxy group, and is the same in the claims and the description below. As the monomer having the formula (1), a compound in which three or more hydroxyl groups of a polyhydric alcohol having three or more alcoholic hydroxyl groups in one molecule are esterified products of (meth) acrylic acid can be used. For example, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa ( (Meth) acrylate, trimethylolpropane tri (meth) acrylate, and the like. These monomers can be used alone or in combination of two or more.

The proportion of the monomer having three or more (meth) acryloyloxy groups in one molecule is preferably 20 to 90% by weight based on the total amount of the polymerizable monomer. More preferably, 30 to 80% by weight. Most preferably 30-7
0% by weight.

The proportion of the monomer used is 20% by weight.
If the amount is less than 90%, the cured film is inferior in scratch resistance, and if the amount is more than 90% by weight, shrinkage due to polymerization is large, distortion is left in the film, and flexibility is unfavorably reduced.

In the present invention, the monomer having one or two ethylenically unsaturated double bonds in one molecule is not particularly limited as long as it is a normal monomer having radical polymerizability. be able to. The following (a) to (f) include those having two ethylenically unsaturated double bonds in one molecule.
(A) having 2 to 12 carbon atoms
(Meth) acrylic acid diesters of alkylene glycols: ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1 (B) (meth) acrylate diesters of polyoxyalkylene glycol such as 6,6-hexanediol di (meth) acrylate: diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate,
(C) (meth) acrylic acid diesters of polyhydric alcohols such as tetraethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and propylene glycol di (meth) acrylate: (D) Bisphenol A or (meth) acrylic acid diesters of bisphenol A hydride ethylene oxide and propylene oxide adducts, such as pentaerythritol di (meth) acrylate: 2,2'-bis (4-acryloxyethoxyphenyl) A) a diisocyanate compound such as propane, 2,2′-bis (4-acryloxypropoxyphenyl) propane, and a terminal isocyanate group obtained by previously reacting two or more alcoholic hydroxyl group-containing compounds; Urethane (meth) acrylates having two or more (meth) acryloyloxy groups in the molecule obtained by reacting the compound with an alcoholic hydroxyl group-containing (meth) acrylate, and (f) two or more in the molecule In the present invention, epoxy (meth) acrylates having two or more (meth) acryloyloxy groups in the molecule obtained by reacting acrylic acid or methacrylic acid with a compound having an epoxy group can be preferably used in the present invention. .

Examples of the compound having one ethylenically unsaturated double bond in one molecule include methyl (meth) acrylate, ethyl (meth) acrylate, n- and i-propyl (meth) acrylate, n- and sec-. , And t
-Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, hydroxyethyl (meth) acrylate, polyethylene glycol Mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycidig (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, N-hydroxyethyl (meth)
Acrylamide, N-vinyl-3-methylpyrrolidone,
N-vinyl-5-methylpyrrolidone or the like can be used. These monomers may be used alone or in combination of two or more. The usage ratio of the monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule is based on the total amount of the monomer.
Preferably from 10 to 80% by weight, more preferably from 20 to 7%.
0% by weight. If the proportion of the monomer used exceeds 80% by weight, it is difficult to obtain a cured film having sufficient scratch resistance, which is not preferable.

On the other hand, if the proportion is less than 10% by weight, the flexibility of the film is lowered and the adhesion to the laminated film provided on the base polyester film is lowered, which is not preferable.

In the present invention, as a method for curing the actinic ray-curable monomer composition used, for example, a method of irradiating ultraviolet rays can be used. It is preferable to add a photopolymerization initiator to the product.

Examples of the photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone,
4,4′-dichlorobenzophenone, 4,4′-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether,
Methyl benzoinformate, p-isopropyl-α-
Carbonyl compounds such as hydroxyisobutylphenone, α-hydroxyisobutylphenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, thioxanthone, 2-chlorothioxanthone, Sulfur compounds such as 2-methylthioxanthone, peroxide compounds such as benzoyl peroxide and di-tert-butyl peroxide, and the like can be used. These photopolymerization initiators may be used alone or in combination of two or more. The use amount of the photopolymerization initiator is preferably from 0.01 to 10 parts by weight based on 100 parts by weight of the active ray-curable monomer composition. When electron beam or gamma ray is used as the curing means, it is not always necessary to add a polymerization initiator.

In the present invention, the actinic ray-curable monomer composition to be used includes hydroquinone, hydroquinone monomethyl ether, 2,5-t-butyl for the purpose of preventing thermal polymerization during production and dark reaction during storage. It is preferable to add a thermal polymerization inhibitor such as hydroquinone. The amount added is preferably 0.005 to 0.05% by weight based on the total weight of the actinic ray-curable monomer composition.

For the purpose of improving workability during coating and controlling the coating film thickness, an organic solvent is blended with the actinic ray-curable monomer composition to be used within a range that does not impair the effects of the present invention. May be done. As the organic solvent, the boiling point is 50 to
Those having a temperature of 160 ° C. are preferably used in view of workability during coating and drying before and after curing. For example, alcohol solvents such as isopropyl alcohol, ketone solvents such as methyl etol ketone and methyl isobutyl ketone, and aromatic solvents such as toluene. Group-based solvents and saturated hydrocarbon-based solvents such as cyclohexanone. These solvents can be used alone or in combination of two or more.

The actinic ray-curable monopolymer composition used in the present invention contains an antioxidant, a light stabilizer, an ultraviolet absorber, a leveling agent, an antistatic agent and the like as long as the effects of the present invention are not impaired. May be blended.

As a method of applying the actinic ray-curable monomer composition, for example, brush coating, dip coating, knife coating, roll coating, spray coating, spin coating (eg, spinner) and the like can be used.

The actinic radiation used in practicing the present invention is an electromagnetic wave such as an ultraviolet ray, an electron beam, or a radiation (α ray, β ray, γ ray, etc.) capable of polymerizing an acrylic vinyl group. Ultraviolet light is simple and preferable, and as an ultraviolet light source,
For example, an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a sequinone lamp, a carbon arc lamp, and the like can be used. Further, the electron beam method is preferably used because the apparatus is expensive and requires operation under an inert gas, but it is not necessary to include a photopolymerization initiator or a photosensitizer in the surface hardness layer. be able to.

The thickness of the surface hardening layer is not particularly limited and may be appropriately selected depending on the application.
μm or more and 10 μm or less, more preferably 1 μm to 5 μm
It is. If the thickness of the surface hardness layer is less than 0.5 μm, the surface hardness is insufficient and the surface is easily damaged, and if it exceeds 10 μm, the cured film becomes brittle and cracks occur during molding after lamination with a steel sheet. Not preferred.

The overlay film obtained according to the present invention is particularly useful for applications requiring weather resistance and scratch resistance, for example,
It can be suitably used as an overlay film for a wall material for a unit bath, an outer frame of a refrigerator, an outer wall of a building, and the like.

[0041]

Next, the present invention will be described based on embodiments.

Example 1 Benzotriazole reactive ultraviolet absorber (2- (2 ′)
-Hydroxy-5'methacryloxyethylphenyl) -2
H-benzotriazole) and methyl methacrylate (copolymerization ratio = 30/70 wt%)
UVA-30M: manufactured by Otsuka Chemical Co., Ltd.) was dissolved in a mixed solution of n-butyl acetate / cyclohexanone (7/3) to obtain a solution having a solid content of 20% by weight. This solution was applied to one surface of a biaxially stretched polyethylene terephthalate film (thickness: 38 μm) so that the thickness after application was 3 μm,
For 2 minutes. The following surface hardness layer was further laminated thereon.

When the pencil hardness of this film was measured, the hardness was 2H.

This film was bonded to a PVC film having a thickness of 100 μm, and further bonded to a steel plate having a thickness of 0.5 mm.

The film was tested for weather resistance using an ultraviolet deterioration accelerating tester, i-super (type SUV-F1 manufactured by Iwasaki Electric Co., Ltd.). As a result, no change in the appearance of the film was observed after 240 hours of irradiation with ultraviolet light. Also, # 00
When the surface was rubbed with 00 steel wool, no surface scratch was found.

[0046]

[Surface Hardening Layer] (1) Coating composition: pentaerythritol triacrylate 60 parts 2.2-bis (4-acryloxydiethoxyphenyl) propane 10 parts N-vinylpyrrolidone 30 parts 1-hydroxycyclohexyl phenyl ketone 4 Part 2- (2, -hydroxy-5, methacryloxyethylphenyl-2H benzotriazole (weather resistance imparting component) 25 parts toluene 90 parts n-butyl acetate 70 parts isopropyl alcohol 70 parts (2) Coating: curing the above coating material After applying it to a thickness of 4 μm and drying the solvent with a hot air drier, it is irradiated with ultraviolet rays for 15 seconds with a high pressure mercury lamp having an irradiation intensity of 80 w / cm and set at a height of 9 cm from the application surface, and then cured. I let it.

Example 2 Benzotriazole reactive ultraviolet absorber (2- (2 ′)
-Hydroxy-5'methacryloxyethylphenyl) -2
H-benzotriazole) and methyl methacrylate (copolymerization ratio = 30/70 wt%)
UVA-30M: manufactured by Otsuka Chemical Co., Ltd.) was dissolved in a mixed solvent of n-butyl acetate / cyclohexanone (7/3) to obtain a solution having a solid content of 20 wt%. To this solution was added 2 parts of a melamine hardener (Cymel 370: manufactured by Mitsui Cyanamid Co., Ltd.).
Was added.

This solution was applied to one side of a biaxially stretched polyethylene terephthalate film (thickness: 38 μm) so that the thickness after application was 3 μm, and dried at 120 ° C. for 2 minutes. Further, the surface hardened layer described in Example 1 was laminated on this laminated film.

When the pencil hardness of this film was measured, the hardness was 2H.

This film was bonded to a PVC film having a thickness of 100 μm, and further bonded to a steel plate having a thickness of 0.5 mm.

The film was tested for weather resistance with an ultraviolet deterioration accelerating tester, i-super (Iwasaki Electric, type SUV-F1). As a result, no change in the appearance of the film was observed after 240 hours of irradiation with ultraviolet light. Also, # 00
When the surface was rubbed with 00 steel wool, no surface scratch was found.

Example 3 Benzotriazole type reactive ultraviolet absorber (2- (2 ′)
-Hydroxy-5'methacryloxyethylphenyl) -2
H-benzotriazole) and methyl methacrylate (copolymerization ratio = 30/70 wt%)
UVA-30M: manufactured by Otsuka Chemical Co., Ltd.) was dissolved in a mixed solvent of n-butyl acetate / cyclohexanone (7/3) to obtain a solution having a solid content of 20 wt%. To this solution was added 2 parts of a melamine hardener (Cymel 370: manufactured by Mitsui Cyanamid Co., Ltd.).
Was added.

This solution was biaxially stretched polyethylene-2,6
-Naphthalate film (38 μm thickness) was coated on one side so that the thickness after coating was 3 μm, and dried at 120 ° C. for 2 minutes. Further, the surface hardened layer described in Example 1 was laminated on this laminated film.

When the pencil hardness of this film was measured, the hardness was 2H.

This film was bonded to a PVC film having a thickness of 100 μm, and further bonded to a steel plate having a thickness of 0.5 mm.

The film was tested for weather resistance with an ultraviolet deterioration accelerating tester, i-super (type SUV-F1, manufactured by Iwasaki Electric Co., Ltd.). As a result, no change in the appearance of the film was observed after 240 hours of irradiation with ultraviolet light. Also, # 00
When the surface was rubbed with 00 steel wool, no surface scratch was found.

[0057]

[Comparative example]

Comparative Example 1 Benzotriazole-based reactive ultraviolet absorber (2- (2 ′
-Hydroxy-5'methacryloxyethylphenyl) -2
H-benzotriazole) and methyl methacrylate (copolymerization ratio = 30/70 wt%)
UVA-30M: manufactured by Otsuka Chemical Co., Ltd.) was dissolved in a mixed solution of n-butyl acetate / cyclohexanone (7/3) to obtain a solution having a solid content of 20% by weight.

This solution was applied to one side of a biaxially stretched polyethylene terephthalate film (thickness: 38 μm) so that the thickness after application was 3 μm, and dried at 120 ° C. for 2 minutes.

This film was bonded to a PVC film having a thickness of 100 μm, and further bonded to a steel plate having a thickness of 0.5 mm.

The film was tested for weather resistance with an ultraviolet deterioration accelerating test machine, i-super (Iwasaki Electric, type SUV-F1). As a result, no change in the appearance of the film was observed after 240 hours of irradiation with ultraviolet light. # 0000
The surface was scratched when the surface was scraped with steel wool.

This film is referred to as Comparative Example 1.

Comparative Example 2 The surface-hardened layer of Example 1 was directly laminated on one surface of a biaxially stretched polyethylene terephthalate film (thickness 38 μm). This film was bonded to a PVC film having a thickness of 100 μm, and further bonded to a steel plate having a thickness of 0.5 mm.

This film was tested for weather resistance with an ultraviolet deterioration accelerating tester, i-super (Iwasaki Denki type SUV-F1). As a result, the film was excellent in scratch resistance, but inferior in adhesion to the base film, and was practically used. It was not suitable.

Comparative Example 3 Biaxially stretched polyethylene terephthalate film (thickness 3
8 μm) was bonded to a 100 μm thick PVC film, and further bonded to a 0.5 mm thick steel plate. The film was tested for weather resistance with an ultraviolet deterioration accelerating tester, i-super (type SUV-F1, manufactured by Iwasaki Electric Co., Ltd.). As a result, the film was poor in scratch resistance and markedly yellowed on the surface.

[Table 1] The following methods were used to measure the characteristics in Table 1.

(A) Weather resistance: Using an ultraviolet deterioration accelerating tester, i-super (Iwasaki Electric type SUV-F1),
An irradiation test was performed for 40 hours, and the appearance change of the film was visually inspected, and those having no change in color were judged to have weather resistance.

(B) Scratch resistance: Judgment was made based on the degree of scratching when the film surface was rubbed 10 times back and forth with # 0000 steel wool.

：: No damage at all.

×: The scratch is clearly visible.

(C) Pencil hardness: In accordance with JIS K5400, the surface of the surface hardness layer was scratched with pencils of various hardnesses, and the hardness was indicated by the pencil hardness at the time of scratching.

(D) Adhesion: A cross-cut was made in the surface weather layer after the eye super irradiation, and a peel test of the surface weather layer was performed using Nichiban cellophane tape (10 mm width). ：: no peeling ×: peeling area is 50% or more

[0071]

According to the present invention, the weather resistance is extremely excellent,
In addition, an overlay film having excellent transparency, blocking resistance and scratch resistance can be obtained.

Claims (5)

[Claims] An overlay film comprising a thermoplastic film as a main component and a surface hardness layer having a pencil hardness of H or more and weather resistance on at least one surface. 2. The overlay film according to claim 1, wherein the thermoplastic film is a polyethylene terephthalate film. 3. The thermoplastic film is polyethylene-2,
The overlay film according to claim 1, wherein the film is a 6-naphthalate film. 4. A layer comprising, as a main component, a benzotriazole monomer copolymerized acrylic resin on a thermoplastic film, and a benzotriazole reactive ultraviolet absorber on the (A) layer. A film for overlay characterized by being laminated with a surface hardness layer (B) having a pencil hardness of H or more. 5. A film overlay steel sheet wherein the overlay film according to claim 1, 2, 3 or 4 is laminated on the steel sheet.