JP2805880B2 - Polyester film coated metal plate - Google Patents

Description

The present invention relates to a polyester film-coated metal plate. Specifically, adhesiveness, moisture and heat resistance, boiling water resistance,
The present invention relates to a polyester film-coated metal plate having excellent properties such as surface hardness and anti-glare properties.

[Prior Art] Conventionally, a laminate obtained by laminating a thermoplastic resin film on a metal plate has been used in fields such as building materials and home appliances. As an example, a polyvinyl chloride resin-coated metal plate,
A polypropylene resin-coated metal plate and the like have been put to practical use. Such a resin-coated metal plate has high corrosion resistance and aesthetics, but has a low surface hardness, and thus cannot be used for applications that emphasize aesthetics, such as refrigerators and audio equipment. In order to solve these disadvantages, a polyester film is laminated on a metal plate via a resin layer (Japanese Patent Application Laid-Open No. 58-39448), and a polyester film and a metal plate are laminated via a print layer (Japanese Patent Application Laid-Open No. 59-39448). −232852).

In addition, recently, applications to applications that are strict in terms of processed finish and surface appearance have been promoted, and surface flaws generated during processing, transportation, movement, handling, and the like have also become a problem. In order to eliminate these disadvantages, a metal plate, a resin layer, a polyester film, and a transparent inorganic compound thin film layer are laminated in this order (JP-A-59-169854), or a metal plate, a resin layer, a thermoplastic resin film, Acrylic UV curable resin layers laminated in this order (Japanese Patent Application Laid-Open No. 64-7522)
9) has been proposed.

[Problems to be Solved by the Invention] However, the above-mentioned conventional polyester-coated metal plate has the following problems. When a polyester film is laminated on a metal plate via a resin layer, the initial adhesion can be secured, but when a durability test such as wet heat resistance, boiling water resistance, weather resistance, etc. is performed, the adhesion between the resin layer and the polyester film Power drops significantly. Alternatively, depending on the type of the resin layer interposed between the metal plate and the polyester film, the adhesiveness is not sufficient from the beginning and the polyester film is not used as a metal film coated with a polyester film.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a durable polyester film-coated metal plate having good adhesion to a metal plate, particularly a resin layer provided on the metal plate. For applications requiring a higher surface hardness, a polyester film-coated metal sheet having higher quality performance is provided by providing a surface hardness layer on the surface of the polyester film. Further, by providing an antiglare layer on the surface of the polyester film, the present invention provides a polyester film-coated metal plate that imparts a three-dimensional sense of depth and an improved concealment effect on the metal plate.

[Means for Solving the Problems] The present invention is characterized by a polyester film-coated metal plate in which a surface-modified layer and a polyester film are laminated on a metal plate via a resin layer in this order.

The polyester referred to in the present invention is a well-known polyester, specifically, for example, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, bis-α, β (2-glophenoxy) ethane-4,4′-dicarboxylic acid, adipic acid And polyesters obtained by polycondensing one kind of bifunctional carboxylic acid such as sebacic acid and at least one kind of ethylene glycol, triethylene glycol, tetramethylene glycol, hexamethylene glycol, and decamethylene glycol. . The polyester may be blended or copolymerized with another polymer within a range not to impair the object of the present invention, and may include an antioxidant, a heat stabilizer, a lubricant, a pigment, an ultraviolet absorber, and the like. You may.
The intrinsic viscosity of the polyester (measured in orthochlorophenol at 25 ° C.) is preferably from 0.4 to 2.0, more preferably from 0.5 to 1.0.

In the present invention, polyethylene terephthalate, polyethylene-2,6-naphthalate, polyethylene-α, β-bis (2-chlorophenoxy) ethane-4,
Particularly excellent effects are obtained when 4'-dicarboxylate is used.

The polyester film constituting the present invention is at least uniaxially oriented by a conventional method, but desirably at least biaxially oriented in view of moldability, opportunity strength, dimensional stability and the like. The thickness of the polyester film is not particularly limited, but is preferably from 5 to 200 μm. If the thickness of the polyester film is less than 5 μm, the workability decreases, and if it exceeds 200 μm, the processability decreases and it is economically disadvantageous, which is not preferable.

The outer surface of the polyester film constituting the present invention (the surface opposite to the surface-modified layer) may be provided with irregularities by a sandblasting method, an embossing method or the like. By forming this unevenness, the reflection of light is effectively scattered,
There is an effect that anti-glare properties can be imparted.

The resin constituting the surface-modified layer (hereinafter abbreviated as “modified layer”) in the present invention is a known resin, for example, a water-soluble or water-dispersible polyester resin having a hydrophilic group in the polyester resin. Polyester resins known in JP-B-47-40873, JP-B-56-5476 and the like, polyester resins in accordance therewith, and water-soluble or water-dispersible polyurethane resins having anionic groups are disclosed in JP-B-42-2419.
4, a polyurethane resin known in Japanese Patent Publication No. 46-7720 or the like, a polyurethane resin similar thereto, a water-soluble or water-dispersible acrylic resin having a hydrophilic group and known in JP-A-52-19786, etc. Acrylic resin or an acrylic resin equivalent thereto. Among these, a low crystalline polyester resin such as a copolymerized polyester is preferred because it improves the adhesiveness between the polyester film and the resin layer. The low-crystalline polyester resin means that at least 70 mol% or more of the dibasic acid component is terephthalic acid residues, and the other dibasic acid component is isophthalic acid,
Aromatic dicarboxylic acids such as orthophthalic acid, succinic acid,
One or more dicarboxylic acids selected from aliphatic dicarboxylic acids such as adipic acid, azelaic acid and sebacic acid, and cyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid and hexahydrophthalic acid. A basic acid residue, wherein at least 60
Mol% or more is an ethylene glycol residue, and other glycol components are alkylene glycols such as 1,4-butanediol, 1,5-pentadiol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, and triethylene glycol. Glycol residues such as glycols, polyalkylene glycols such as 1,4-cyclohexanediol, ethylene oxide and propylene oxide adducts of bisphenol A, and 1,4-cyclohexanedimethanol. Crystalline copolymerized polyesters and the like can be mentioned.

Of these, 75 mol% to 95 mol% of terephthalic acid, 25 mol% to 5 mol% of a dibasic acid other than terephthalic acid, and a copolymerized polyester comprising ethylene glycol are desirable,
Copolyesters comprising 80 mol% to 90 mol% of terephthalic acid, 20 mol% to 10 mol% of dibasic acids other than terephthalic acid, and ethylene glycol are particularly desirable.

From the viewpoint of the easiness of synthesis of the copolymerized polyester and the ease of forming a laminated film, a copolymerized polyester in which the dibasic acid is terephthalic acid and isophthalic acid and the glycol is ethylene glycol is preferable. It is preferable that the content is 93 mol% and the content of isophthalic acid is 18 to 7 mol% in terms of adhesiveness and boiling water resistance.

Further, particularly, a hydrophilic group-containing polyester resin [A]
And a copolymer [C] obtained by grafting the compound [B] having at least one or more unsaturated bonds to the resin [A].
A layer composed of a composition containing a cross-linking agent as a main component is preferable because the adhesiveness between the polyester film and the resin layer is further improved.

The hydrophilic group-containing polyester resin [A] (hereinafter abbreviated as resin [A]) in the present invention refers to a hydrophilic group or a hydrophilic component in a molecule such as a hydroxyl group, a carboxy group, a carbonyl group, a cyano group, an amino group, Methylcarbonyl group, polyethylene glycol, carboxylate, phosphate ester salt,
It is a polyester copolymer into which at least one or more of quaternary ammonium salts, sulfate salts, sulfonates and the like have been introduced. Among them, those having the following compositions are useful as typical polyester copolymers. That is, a polycondensate of an aromatic dicarboxylic acid and / or a non-aromatic dicarboxylic acid and an ester-forming alkali metal salt of a sulfonic acid with glycol is exemplified.

The resin [A] may be water-soluble or water-dispersible, and its solubility depends on the type of the copolymer composition, the mixing ratio, the presence or absence of the addition of the hydrophilic organic compound used as the dispersion stability imparting agent, and the type thereof. The amount of the hydrophilic organic compound added is preferably small, as long as the dispersion stability is not impaired. The hydrophilic organic compound is an aliphatic or alicyclic alcohol, ester, ether or ketone.

In the present invention, the glass transition temperature (Tg) of the resin [A] is 30 to
It is desirably in the range of 80 ° C, preferably 50 to 75 ° C. When the glass transition temperature of the resin [A] is less than 30 ° C., the modified layer becomes inferior in water resistance and heat resistance, and various adverse effects increase. 80
If the temperature exceeds ℃, the dispersion stability is poor, and it is extremely difficult to graft a compound having an unsaturated bond. Resin [A] can be produced by a usual polyester production technique. That is, the above-mentioned acid component and glycol component are subjected to melt polycondensation using a reaction catalyst such as esterification or a transesterification catalyst or a polymerization catalyst to obtain a desired polymer. Furthermore, solution polycondensation can be applied.

The compound [B] having an unsaturated bond (hereinafter abbreviated as compound [B]) as referred to in the present invention is a compound which is grafted to the resin [A], and specifically includes vinyl esters and unsaturated carboxylic acid esters. , Unsaturated carboxylic acid amides,
Examples thereof include unsaturated nitriles, unsaturated carboxylic acids, and acrylic compounds, and at least one selected from these is applied, but is not particularly limited.

The grafted copolymer [C] (hereinafter abbreviated as copolymer [C]) referred to in the present invention is obtained by grafting the compound [B] to the resin [A]. The polymer [C] is produced by a conventional graft polymerization method. That is, the reaction is performed by adding the compound [B] in the presence of a water-soluble or water-dispersible polymerization initiator in an aqueous medium system of the resin [A].

In the present invention, the grafting ratio of the compound [B] to the resin [A] is 0.5 to 600%, more preferably 5 to 300%, particularly 10 to 100%.
% Is desirable. 0.5% grafting rate
If it is less than 1, the solvent resistance and water resistance of the modified layer deteriorate, which is not preferable. If the grafting ratio exceeds 600%, the coatability is deteriorated and the adhesion between the modified layer and the polyester film is lowered, which is not preferable.

The cross-linking agent referred to in the present invention is thermally cross-linked with a functional group present in the resin [A] or the polymer [C], for example, a hydroxyl group, a carboxyl group, a glycidyl group, an amide group, and finally, three-dimensionally. It is a crosslinking agent for forming a modified layer having a network structure.

In the present invention, it is preferable to use a melamine-based crosslinking agent, a urea-based crosslinking agent, or an epoxy-based crosslinking agent as a crosslinking agent, since a modified layer having a particularly large crosslinking effect and excellent water resistance and solvent resistance can be obtained. These crosslinking agents may be used alone or in combination of two or more in some cases. The amount of the crosslinking agent to be added is preferably 0.001 to 60 parts by weight, more preferably 0.01 to 20 parts by weight, per 100 parts by weight of the solid content in the mixture of the resin [A] and the polymer [C]. If the amount is less than 0.001 part by weight, the crosslinking effect is low, and the solvent resistance and alkali resistance of the modified layer deteriorate. If the amount exceeds 60 parts by weight, the adhesiveness of the surface-modified layer is reduced, and the coatability is further deteriorated, so that it is difficult to form a uniform layer.

The weight mixing ratio of the polymer [C] and the resin [A] in the modified layer is preferably in the range of 90/10 to 5/95, more preferably 60/40 to 30/70. If the polymerization mixture ratio of the polymer [C] is less than 5%, the solvent resistance, alkali resistance and water resistance of the modified layer are undesirably reduced. If it exceeds 90%, the adhesion of the modified layer to the polyester film is undesirably reduced.

Further, the modified layer may contain a known crosslinking catalyst and an adhesion promoter, and if necessary, known additives such as an antifoaming agent, an antistatic agent, a pigment, a dye, a lubricant and a thickener.

The thickness of the surface modified layer constituting the present invention is 0.005 to 10.0 μm.
m is preferable, and the range of 0.01 to 5.0 μm is more preferable.
If the thickness of the modified layer is less than 0.005 μm, uniform lamination is difficult,
It is difficult to obtain sufficient adhesion. If the thickness exceeds 10.0 μm, the slip property of the modified layer tends to deteriorate.

In particular, when the surface-modified layer is provided on the polyester film and then stretched in at least one direction, it is preferable because the adhesion to the polyester film is further improved.

In the present invention, the modified layer is indispensable to be interposed between the resin layer and the polyester film. However, when the surface hardening layer and / or the antiglare layer described later is further laminated on the polyester film side, A modified layer can be similarly interposed between the polyester film and the surface hardening layer and / or the antiglare layer. By doing so, not only the adhesiveness between the polyester film and the resin layer is excellent, but also the adhesiveness between the polyester film and the surface hardening layer and / or the anti-glare layer is remarkably improved, and the wet heat resistance, boiling water resistance Has a remarkable effect.

As the metal plate, mild steel plate, copper foil, iron foil, aluminum plate, or single plating of zinc, lead, aluminum, copper, chromium or nickel, or alloy plating steel plate of two or more of these, zinc as a main component Alloy-plated steel sheets, cut sheets or strips of chemical conversion-treated steel sheets with chromate or phosphate or the like. Of course, the plated steel sheet may be either electrolytic or molten, or may be subjected to chemical conversion treatment after plating.

As a resin layer interposed between the surface modified layer and the metal plate laminated on the polyester film, polyester resin, urethane resin, acrylic resin, synthetic rubber resin, polyamide resin, PVC resin, epoxy resin, phenol resin , Ionomer resin, modified olefin resin, etc.
It consists of species or two or more species. In particular, polyester resin, urethane resin, and PVC resin are preferable in terms of adhesiveness to a metal plate and a surface modification layer, and crack resistance during bending and forming. These resins are in solution,
It can be used in any form of film, powder, or pellet, and may be appropriately selected depending on the purpose and use. Colorants such as inorganic pigments and organic pigments, UV absorbers, heat stabilizers, antioxidants, flame retardants, lubricants and other additives can be added to the resin layer as needed.

The thickness of the resin layer may be adjusted as necessary,
μm is preferred.

In addition, a printed layer such as a design and a picture may be provided between the resin layer and the modified layer as long as the object of the present invention is not impaired.

As the surface hardness layer in the present invention, acrylic,
Examples include urethane-based, melamine-based, organic silicate, silicone-based, and metal oxides. Particularly, a silicone type and an acrylic type are preferable in terms of hardness, durability, and the like, and an acrylic type, particularly, an active ray-curable acrylic type is preferable in terms of curability, flexibility, and productivity.

The actinic ray-curable acrylic resin contains an acrylic oligomer and a reactive diluent as actinic ray polymerization components, and may further contain, if necessary, a photoinitiator, a photosensitizer, and a modifier. Acrylic oligomers include polyester acryl, urethane acryl, epoxy acryl, and polyether acryl, as well as those in which a reactive acryl group is bonded to an acrylic resin skeleton. In addition, examples include those in which an acrylic group is bonded to a rigid skeleton such as melamine or isocyanuric acid, but the present invention is not limited thereto. The reactive diluent is a solvent for the coating process as a medium for the coating agent, and itself has a group that reacts with a monofunctional or polyfunctional acrylic oligomer. It is what becomes. Further, particularly in the case of crosslinking by ultraviolet rays, since the light energy is small, a photopolymerization initiator and a sensitizer are required for conversion of light energy and promotion of initiation. Specific examples of these acrylic oligomers, reactive diluents, photopolymerization initiators, sensitizers, crosslinking devices, etc. are described in Shinzo Yamashita and Tosuke Kaneko, "Handbook of Crosslinking Agents" Taiseisha, 1981, pp. 267 to 267. 275 pages, Chapter
Pages 562 to 593 can be referred to, but are not limited thereto. Commercially available products such as Mitsubishi Rayon, Fujikura Kasei, Dainichi Seika, Dainippon Ink and Chemicals, Toa Gosei Chemicals, Nitto Kasei, etc. Is not limited to these. Coating improver, defoamer, thickener, antistatic agent, inorganic particles, organic particles, organic lubricant, organic polymer, dye, pigment, stability These are used as a composition of the coating layer within a range that does not inhibit the reaction by the actinic ray, and can improve the characteristics of the surface hardened layer according to the application.

Further, the composition of the surface hardness layer used in the present invention,
For the purpose of improving workability during coating and controlling the coating film thickness, an organic solvent can be blended within a range that does not impair the object of the present invention.

Among these, in particular, at least one monomer (D) having three or more (meth) acryloyloxy groups in one molecule, and two (meth) acryloyl in one molecule having a tricyclo ring structure It is composed of a composition mainly composed of at least one monomer (E) having an oxy group and at least one polymer (F) having one ethylenically unsaturated double bond in one molecule. The surface-hardened layer is preferred because it can further improve the hardness and curability, as well as the bendability after lamination with a metal plate.

As the monomer (D) having three or more (meth) acryloyloxy groups in one molecule according to the present invention, the hydroxyl group of a polyhydric alcohol having three or more alcoholic hydroxyl groups in one molecule can be used. A compound which is an esterified product of three or more (meth) acrylic acids is exemplified. Here, the (meth) acryloyloxy group means an acryloyloxy group or a methacryloyloxy group, and the esterified (meth) acrylic acid means an esterified acrylic acid or an esterified methacrylic acid. The same applies to the following description, including specific examples.

Specific examples include pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Examples thereof include dipentaerythritol hexa (meth) acrylate and trimethylolpropane tri (meth) acrylate.

These monomers (D) may be used alone or in combination of two or more.

The usage ratio of the monomer (D) is preferably 20 to 80% by weight, more preferably 30 to 80% by weight, and particularly preferably 3 to 70% by weight based on the total amount of the polymerizable monomer.

When the amount of the monomer (D) is less than 20% by weight, a cured film having a sufficient abrasion resistance cannot be obtained. It is not preferable because distortion remains in the film, flexibility of the film is reduced, and curl is largely curled toward the cured film side.

The monomer (E) in the present invention is a bifunctional monomer having two (meth) acryloyloxy groups in one molecule having a tricyclo ring structure represented by the following general formula (1). .

(Wherein, R represents a hydrogen atom or a methyl group.) Examples of such a bifunctional monomer (E) include tricyclodecane dimethanol diacrylate (for example, Nippon Kayaku Co., Ltd .; -684) is a particularly effective component for forming a cured film having low viscosity, good dilutability, good curability, and low polymerization shrinkage.

The usage ratio of these monomers (E) is preferably from 10 to 70% by weight, more preferably from 20 to 70% by weight, and particularly preferably from 20 to 65% by weight, based on the total amount of the polymerizable monomers.

When the amount of the monomer (E) is less than 10% by weight, the flexibility of the cured film is reduced, and a crosslinked cured film having sufficient bending workability cannot be obtained. %, It is not preferable because a cured film having sufficient wear resistance cannot be obtained.

The monomer (F) having one ethylenically unsaturated double bond in one molecule in the present invention includes the following (F ₁ )
It can be exemplified compounds of (F _2).

Examples of (F ₁ ) include compounds in which the ethylenic bond is a (meth) acryloyloxy group and has a polar substituent such as an alcoholic hydroxyl group or a cyclic ether.
More specific examples include 2-hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate,
Examples thereof include tetrahydrofurfuryl (meth) acrylate, ethoxyethyl (meth) acrylate, and ethyl carbitol (meth) acrylate.

(F ₂ ) includes a polymerizable monomer comprising a substituted or unsubstituted N-vinylpyrrolidone-based compound. More specific examples include N-vinylpyrrolidone, N-vinyl-3-methylpyrrolidone, N-vinyl-5-methylpyrrolidone, and the like.

These monomers having one ethylenically unsaturated double bond in one molecule have a low viscosity and a good dilutability, and a cross-linked cured film having a uniform cured film surface and extremely excellent surface smoothness. Is formed.

Further, among these monomers (F), as the monomer (F ₁ ), tetrahydrofurfuryl (meth) acrylate,
As the monomer (F ₂ ), N-vinylpyrrolidone has good curability of the hardened layer, initial adhesion, water resistance, boiling water resistance,
It is a component effective for forming a cured film having good wet heat resistance, and is particularly industrially easily available and easy to use.

These monomers (F ₁ ) and (F ₂ ) may be used alone or as a mixture of two or more.

The ratio of the monomer (F) used is based on the total amount of the polymerizable monomer.
The range is preferably from 11 to 40% by weight, more preferably from 11 to 30% by weight.

When the amount of the monomer (F) is less than 11% by weight, it is difficult to obtain a cured film having sufficient adhesiveness to the substrate,
If the amount exceeds 40% by weight, the abrasion resistance decreases, which is not preferable.

One method of curing the radiation-curable composition of the present invention is to emit ultraviolet light. In this case, it is desirable to add a photopolymerization initiator to the composition. Specific 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, methylbenzoylformate, p-isopropyl-α-hydroxyisobutylphenone, α-hydroxyisobutylphenone 2,2-dimethoxy-2-phenylacetophenone,
Carbonyl compounds such as 1-hydroxycyclohexylphenyl ketone, sulfur compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, thioxanthone, 2-chlorothioxanthone and 2-methylthioxanthone, benzoyl peroxide, di-t-butyl pearl oxide and the like And the like. These photopolymerization initiators may be used alone or in combination of two or more.
The use amount of the photopolymerization initiator is suitably 0.01 to 10 parts by weight based on 100 parts by weight of the polymerizable monomer composition. When electron beam or gamma ray is used as the curing means, it is not always necessary to add a polymerization initiator.

The radiation-curable composition used in the present invention has a known thermal polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, 2,5-t-butylhydroquinone, and the like to prevent thermal polymerization during production and dark reaction during storage. It is desirable to add an agent. The amount added is based on the total weight of the polymerizable compound.
0.005 to 0.05% by weight is preferred.

Actinic radiation means electromagnetic waves that polymerize acrylic vinyl groups such as ultraviolet rays, electron beams, and radiation.
Ultraviolet light is convenient and preferred. The electron beam method is advantageous in that the apparatus is expensive and needs to be operated under an inert gas, but it is not necessary to include a photopolymerization initiator or a photosensitizer in the coating layer.

The thickness of the surface hardness layer is preferably 0.5 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less. When 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 when the thickness exceeds 10 μm,
The cured film is apt to be brittle, and the cured film is liable to crack in bending molding, which is not preferable.

Further, a print layer such as a design and a picture may be provided as the outermost layer of the surface hardness-hardening layer within a range not to impair the object of the present invention.

The anti-glare layer in the present invention may be any layer that reduces the brightness and clarity of the reflection image of the external light source, and may be a well-known layer, for example, by spraying fine powder solids on the surface of a polyester film to reduce unevenness. By sandplasting method, using glass, molds, or rolls processed into an uneven shape, and transferring the uneven surface, paint that forms the uneven shape, or silicon oxide particles or organic filler And a laminate of a composition comprising a paint containing a matting agent. (For example, JP-A-61-2091
54). In particular, a composition obtained by laminating a composition comprising a dye in which a matting agent is blended with a composition for forming a surface hardness layer is preferable because it has excellent surface hardness and scratch resistance and has antiglare properties. Also, irregularities can be provided on the surface of the surface hardness layer by an embossing method or the like.

In the above-mentioned metal sheet coated with a polyester film of the present invention, in order to make the polyester film and the surface hardening layer and / or the antiglare layer more firmly adhere to each other, a corona is applied to the polyester film surface in contact with the surface hardening layer and / or the antiglare layer. An electric discharge treatment may be performed, and an anchor treatment may be performed using a known anchor treatment agent such as a urethane resin, an epoxy resin, an acrylic resin, or a polyester resin. Particularly when using an anchor treatment agent consisting of a reaction product of a vinyl-based copolymer containing a hydroxyl group and a partial ester group of phosphoric acid and a polyisocyanate compound, the surface-modified layer used as a component of the present invention, In particular, the adhesiveness is improved, and a polyester film-coated metal sheet having excellent durability such as wet heat resistance and boiling water resistance can be obtained.

[Production Method] Next, an example of a method for producing the polyester film-coated metal sheet of the present invention will be described. However, it is not limited to the following production method.

First, after the polyester pellets polymerized by a conventional method are sufficiently dried, they are supplied to a known extruder and melted into a sheet from a slit-shaped die at a temperature not lower than a temperature at which the pellets melt and a temperature at which the polymer is decomposed. Extruded, cooled and solidified to make an unstretched sheet. At this time, the intrinsic viscosity of the unstretched sheet is desirably 0.5 or more from the viewpoint of film properties. Next, on the unstretched sheet, or on a film obtained by stretching the unstretched sheet 2.0 to 8.0 times at 70 to 140 ° C,
Apply a surface-modified layer coating material prepared in a predetermined amount on one or both sides, and at 70 to 160 ° C while drying the coating film, when using an unstretched film, 2.0 to 8.0 times in the longitudinal direction, in the horizontal direction. 2.0
~ 8.0 times stretching, 2.0 when using a uniaxially stretched film
Stretch horizontally up to 8.0 times. Further, the biaxially oriented film thus obtained is further heated at 100 to 180 ° C. in at least one direction at 1.1 ° C.
It may be stretched up to 3.0 times. Further, the biaxially oriented film may be provided with a relaxation of 0 to 10% at 150 to 240 ° C.
Heat-treat for 60 seconds.

The application method is not particularly limited, and an extrusion lamination method or a melt coating method may be used, but a gravure coating method of a water-soluble or water-dispersed coating material because a thin film can be coated at a high speed, Reverse coating method,
It is preferable to apply a known method such as a kiss coat method, a die coat method, and a metaling bar coat method. On this occasion,
By applying a known surface treatment such as a corona discharge treatment in the air or in various other atmospheres as necessary before coating on the film, not only the coating properties are improved, but also the modified layer becomes more solid. Can be formed on the film surface.
The concentration of the coating material and the conditions for drying the coating film are not particularly limited, but the drying conditions for the coating film are desirably performed within a range that does not adversely affect the properties of the laminated polyester film.

Next, the surface-hardened layer and / or the surface of the non-modified layer of the laminated film, the surface on which the anchor coating layer is provided on the non-modified layer surface, or the surface of the modified layer in the case of the double-sided modified layer lamination. As a method of applying the glare layer, commonly applied application methods such as brush coating, dip coating, knife coating, roll coating, spray coating, flow coating, and spin coating (such as spinner) can be easily applied. . It is appropriately selected depending on the purpose of use, application, and the like.

Next, as a method for obtaining the polyester film-coated metal sheet of the present invention. Well-known ones, for example, (1) a method of applying or laminating a resin layer on a metal plate, and then laminating and heating a polyester film having a modified layer laminated thereon in advance, and (2) a polyester film having a modified layer laminated in advance. A method of applying or laminating a resin layer on the modified layer, laminating with a metal plate and heating, and the like. However, any method can be applied.

Further, as a method for obtaining a polyester film-coated metal plate provided with a surface hardening layer and / or an antiglare layer on the outermost layer, there are known methods, for example, (1) a modified layer and a surface hardness After providing a functionalized layer and / or an anti-glare layer, laminating the modified layer surface of the polyester film and a metal plate via a resin layer and heating, (2) connecting the metal plate and the polyester film via the resin layer After laminating, a method of providing a surface hardening layer and / or an antiglare layer on the polyester film may be mentioned, but any method may be applied.

[Use] The polyester-coated metal sheet of the present invention thus obtained is generally used as a precoated steel sheet in a wide range of fields such as home appliances, office equipment, building materials, vehicles, and steel furniture. In particular, it is preferable to use it as an exterior member for home appliances, audio equipment, etc. because of its excellent design and sharpness.

[Characteristic evaluation method and evaluation criteria] (1) Adhesiveness A cross cut (100 squares of 1 mm ² ) was put on the surface of the coated metal plate coated with polyester film until it reached the metal plate surface, and cellophane was placed on it. An adhesive tape (Nichiban Co., Ltd. “Cellophane tape” CT-24) was applied, and the degree of peeling after the cellophane adhesive tape was peeled off by hand was observed and evaluated according to the following criteria.

：: good (peeling area less than 5%) △: slightly poor (peeling area 5% or more and less than 20%) ×: poor (peeling area 20% or more) (2) Moisture and heat resistance Constant temperature and humidity layer (Platinus Co., Ltd.) Using a Humider PH-1G), a wet heat test was performed at 60 ° C and 90% RH, and the appearance changes such as cracks were observed.
Further, the wearability test of the above (1) was similarly performed.

(3) Boiling Water Resistance After the coated metal plate was immersed in boiling water for 1 hour, abnormalities in appearance such as cracks were observed, and an adhesion test similar to (1) was performed.

(4) Scratch resistance The polyester film-coated surface was rubbed with steel wool # 0000, and the degree of scratching was evaluated according to the following criteria.

 S3: Hardly scratched even with strong friction.

 S2: If you rub very strongly, you will get a little scratch.

 S1: Scratch even with weak friction.

(5) Pencil hardness In accordance with JIS K5400, pencils of various hardness are applied to the surface coated with polyester film at an angle of 90 ° C and scratched under a load of 1 kg. Displayed with.

(6) Bending workability According to JIS G3312, the coated metal plate was bent at 3T with the polyester film-coated side outside, and the cracking and peeling state of the coating layer was evaluated according to the following criteria.

 ：: No cracking or peeling.

Δ: No cracks are observed, but there is peeling or
No peeling was observed but cracks were observed on the surface layer.

 ×: Cracking was observed on the entire surface and peeled off.

(7) Glossiness Using a glossiness measurement device (Suga Test Instruments Co., Ltd. Digital Variable Glossmeter UGV-4D), incident angle 60 according to JIS Z-8741.
C. Surface gloss was measured.

[Examples] Next, examples of the present invention will be described. However, the present invention is not limited to the following examples. In the examples, parts and% mean parts by weight and% by weight, respectively.

Example 1 A polyethylene terephthalate polymer chip (intrinsic viscosity: 0.62) produced by a conventional method was vacuum-dried at 180 ° C. for 2 hours. This chip is supplied to an extruder, melted at 280 ° C., extruded from a T-shaped die, wound around a cooling drum having a surface temperature of 20 ° C., cooled and solidified to form an unstretched film, and then heated to 90 ° C.
And stretched 3.3 times in the machine direction by roll stretching. Next, acrylamine-grafted water-dispersible polyester copolymer "PESRESIN" 604G (manufactured by Takamatsu Yushi Co., Ltd.) was diluted with water and diluted with a melamine-based cross-linking agent "Nikalac" MW-12LF (a cross-linking agent). (Manufactured by Sanwa Chemical Co., Ltd.) was added in an amount of 4 parts by weight based on 100 parts by weight of resin solids, and a silica sol “Cataroid” having an average particle diameter of 0.10 μm was further used as a lubricant.
(Catalyst Chemical Co., Ltd.) was added in an amount of 0.5 part by weight based on 100 parts by weight of the resin solid content, and a coating agent having a concentration of 3.0% by weight was applied to one surface of the uniaxially stretched film by a metaling bar method. The coated layer is stretched 3.5 times in the horizontal direction at 100 ° C. while drying, and heat-treated at 220 ° C. for 5 seconds while relaxing 3% in the horizontal direction to obtain a 25 μm-thick laminated polyester film on which the modified layer 0.1 μm is laminated. Obtained.

A 100 μm vinyl chloride resin film is laminated on a hot-dip galvanized steel sheet (zinc adhesion amount 60 g / m ² ) with a clean surface of 0.5 mm thickness, and then heated to 250 ° C. to modify the surface of the above-mentioned laminated polyester film. The surface of the polymer layer and the surface of the vinyl chloride resin film were laminated, immediately cooled, and a metal plate coated with a polyester film was obtained.

As shown in Table 1, the obtained polyester film-coated metal sheet had good adhesiveness, heat and moisture resistance, and boiling water resistance.

Example 2 After a polyester resin ("Vylon 20S" manufactured by Toyobo Co., Ltd.) was applied to the same metal plate as in Example 1 and baked, the coated surface and the surface-modified layer surface of the laminated polyester film used in Example 1 were used. Was laminated in the same manner as in Example 1 to obtain a polyester film-coated metal plate. As shown in Table 1, this polyester film-coated metal sheet had good adhesiveness, moisture and heat resistance and boiling water resistance.

Example 3 A low-crystalline polyester resin having the following composition was synthesized by a conventional method.

Composition of low crystalline polyester resin Acid component Terephthalic acid 82.5 mol% Isophthalic acid 17.5 mol% Alcohol component Ethylene glycol 100 mol% This resin was laminated on polyethylene terephthalate by coextrusion to form an unstretched film. Next, the film was biaxially stretched in the longitudinal and transverse directions, and heat-treated to obtain a laminated film having a thickness of 25 and a total thickness of 25 μm with a low-crystalline polyester resin layer and a polyethylene terephthalate layer having a thickness of 1: 9.

Next, the vinyl chloride resin film surface of the vinyl chloride resin film-coated metal plate used in Example 1 and the surface-modified layer surface were laminated in the same manner as in Example 1 to obtain a polyester film-coated metal plate.

As shown in Table 1, this metal sheet coated with a polyester film was excellent in adhesiveness, hot water resistance and boiling water resistance.

Comparative Example 1 A biaxially oriented film was obtained in the same manner as in Example 1 except that the coating agent was not applied, and then bonded to a metal plate coated with a vinyl chloride resin film in the same manner as in Example 1 to obtain a polyester film-coated metal plate. I got As shown in Table 1, the adhesiveness of this metal sheet coated with a polyester film was not good at all. Further, the wet heat resistance and the boiling water resistance were not good because the adhesiveness was remarkably reduced.

Comparative Example 2 A biaxially oriented film was obtained in the same manner as in Example 1 except that the coating agent was not applied, and then a polyester resin ("Byron 20S" manufactured by Toyobo Co., Ltd.) was applied to a metal plate and baked. Lamination was performed in the same manner as in Example 1 to obtain a polyester film-coated metal plate. As shown in Table 1, this metal sheet coated with a polyester film had good adhesiveness, but poor wet heat resistance and boiling water resistance.

Example 4 70 parts by weight of dipentaerythritol hexaacrylate and 30 parts by weight of N-vinylpyrrolidone were formed on one surface of the modified layer using a laminated film having a surface modified layer on both sides in the same manner as in Example 1. Part, 1-hydroxycyclohexyl phenyl ketone (Ciba Geigy “IRUGACURE” 184) 4
The composition obtained by stirring and mixing the parts by weight was uniformly applied using a bar coater so that the film thickness after curing became 3 μm. This was cured at a speed of 3 m / min under a high-pressure mercury lamp (manufactured by Toshiba) having an intensity of 80 W / cm and set at a height of 12 cm from the coated surface to obtain a laminate.

The surface-modified layer on the polyester film surface of this laminate and the vinyl chloride resin film surface of the vinyl chloride resin film-coated metal plate used in Example 1 were laminated in the same manner as in Example 1 to obtain a polyester film-coated metal plate. Obtained.

The evaluation results of the obtained metal sheet coated with a polyester film were excellent in scratch resistance as shown in Table 1 and good in adhesiveness, wet heat resistance and boiling water resistance.

Example 5 Using a laminated film having a surface-modified layer provided on both surfaces in the same manner as in Example 1, 44 parts by weight of dipentaerythritol hexaacrylate and tricyclodecanedimethanol 28 parts by weight of acrylate, 28 parts by weight of tetrahydrofurfuryl acrylate, 5 parts by weight of 1-hydroxycyclohexyl phenyl ketone, 90 parts by weight of toluene
Parts by weight, 70 parts by weight of butyl acetate, isopropyl alcohol
The composition obtained by stirring and mixing 70 parts by weight was uniformly applied using a bar coater so that the film thickness after curing became 3 μm. This was dried at 80 ° C. for 18 seconds, and cured at a speed of 5 cm / min under a high-pressure mercury lamp having an intensity of 80 w / cm set at a height of 12 cm from the application surface in the air to obtain a laminate. .

The surface-modified layer on the polyester film surface of this laminate and the vinyl chloride resin film surface of the vinyl chloride resin film-coated metal plate used in Example 1 were laminated in the same manner as in Example 1 to obtain a polyester film-coated metal plate. Obtained.

As shown in Table 1, the evaluation results of the obtained metal sheet coated with a polyester film were excellent in scratch resistance, and good in adhesion, wet heat resistance and boiling water resistance. Furthermore, the bending workability was good without cracking and peeling of the coating layer, despite the surface hardness layer being laminated.

Example 6 70 parts by weight of dipentaerythritol hexaacrylate and 30 parts by weight of N-vinylpyrrolidone were formed on one surface of the modified layer using a laminated film having a surface modified layer provided on both sides in the same manner as in Example 1. Parts, 1 part by weight of 1-hydroxydichloxyphenyl ketone, silica powder (OK-41, manufactured by Degussa Co., Ltd.)
2, average particle diameter 4μ) 3 parts by weight, butanol 70 parts by weight,
A composition obtained by stirring and mixing 80 parts by weight of toluene was uniformly applied using a bar coater so that the film thickness after curing became 3 μm. After drying at 80 ° C for 30 seconds, 3 m under a high-pressure mercury lamp with an intensity of 80 W / cm set at a height of 12 cm from the application surface
/ Min to obtain a laminate.

The surface-modified layer on the polyester film surface of this laminate and the vinyl chloride resin film surface of the vinyl chloride resin film-coated metal plate used in Example 1 were laminated in the same manner as in Example 1 to obtain a polyester film-coated metal plate. Obtained.

As shown in Table 1, the evaluation results of the obtained metal sheet coated with a polyester film are excellent in anti-glare properties, completely hide the background color of the metal sheet, and have good adhesion, wet heat resistance and boiling water resistance. there were.

[Effects of the Invention] The polyester film-coated metal sheet of the present invention has the following excellent effects because the surface modified layer is provided between the polyester film and the resin layer.

(1) There is no peeling or tearing of the coating layer due to bending, drawing, etc., and it has excellent processing adhesion and can perform processing with a high degree of processing deformation.

(2) Since the modified layer is excellent in wet heat resistance and water resistance, the firmly formed polyester film-coated metal sheet withstands a long-time wet state and does not decrease in adhesiveness.

(3) Further, by laminating a surface hardness layer on the surface of the polyester film, the scratch resistance is improved, and the service life is increased.

(4) By laminating an antiglare layer on the surface of the polyester film, light can be scattered to prevent glare, a three-dimensional appearance with a deep appearance can be obtained, and an aesthetic effect is imparted.

Claims (4)

(57) [Claims] 1. A polyester film-coated metal plate comprising a metal plate and a surface-modified layer and a polyester film laminated in this order via a resin layer. 2. A polyester film-coated metal sheet comprising a polyester film-coated metal sheet according to claim 1 and a surface hardening layer laminated on the polyester film side. 3. A polyester film-coated metal plate comprising the polyester film-coated metal plate according to claim 1 and an antiglare layer laminated on the polyester film side. 4. A copolymer [C] having a surface-modified layer obtained by grafting a hydrophilic group-containing polyester resin [A] and a compound [B] having at least one or more unsaturated bonds to the resin [A]. And a copolymer [C] containing a crosslinking binder as a main component.
The grafting ratio of the copolymer [C] is 0.5 to 600%, and the weight mixing ratio of the copolymer [C] and the resin [A] is 90/10 to 5/95. 4. The metal sheet coated with a polyester film according to item 1.