JP2002079635A - Laminated polyester film and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film with improved adhesive properties on various coated articles and at the same time, with improved adhesive properties after wet heat treatment. SOLUTION: In a process for manufacturing a polyester film, a laminated film forming coating in which at least one resin selected from acrylic resins, polyester resins and urethane resins is a main constituent ingredient is applied on at least one face of the polyester film before crystallization orientation is completed and then, it is drawn in at least one direction and is heat-treated and thereafter, electrical discharge machining is applied on the laminated film under nitrogen atmosphere to manufacture the laminated polyester film with a waterdrop contact angle on the surface of the laminated film of at least 50 degree.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a laminated polyester film, and more particularly, the present invention relates to a laminated polyester film having excellent adhesion to various coatings and excellent adhesion after wet heat treatment. And a method of manufacturing the same.

[0002]

2. Description of the Related Art Polyester films, especially biaxially oriented polyester films, have excellent properties such as dimensional stability, mechanical properties, heat resistance, transparency, electrical properties and chemical resistance. It is widely used as a base film for many applications such as packaging materials, electrical insulating materials, various photographic materials and graphic arts materials.

[0003] However, biaxially oriented polyester films generally have a drawback of poor adhesion to various paints and inks because their surfaces are highly crystal-oriented. For this reason, conventionally, studies have been made to impart adhesiveness to the polyester film surface by various methods.

Conventionally, as a method of imparting adhesiveness to the surface of a polyester film, various types of easy-adhesion treatment, such as corona discharge treatment, ultraviolet irradiation treatment or plasma treatment, are applied to a polyester film as a base film. Investigations include methods for chemical conversion, surface etching with chemicals such as acid, alkali or amine aqueous solutions, and methods for providing various resins such as acrylic resin, polyester resin, urethane resin, or polyolefin resin with adhesive on the film surface as a primer layer. Have been.

[0005] In particular, the method of providing a primer layer on a base film is capable of selecting and coating an adhesive substance compatible with various coating materials. An acrylic resin, a urethane resin, an acrylic graft polyester resin, or the like as an adhesive substance, which is laminated on a polyester film has been proposed (Japanese Patent Application Laid-Open No. 55-1).
No. 5825, JP-A-58-78761, JP-A-60-248232, JP-A-62-24944.
0, JP-A-1-108037 and JP-A-4-263937).

[0006] An easily adhesive polyester film in which a coating layer is provided on a polyester film and the coating layer is subjected to electric discharge machining has also been proposed (JP-A-58-5338).

[0007]

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

In terms of adhesion to the coating, the polyester resin constituting the film has poor adhesion, and the acrylic resin or urethane resin constituting the primer layer often has insufficient adhesion. Further, a melamine crosslinking agent or the like may be added and used to improve the adhesiveness. However, when the coating is adhered to the substrate film surface and stored under moisture and heat resistance, the adhesiveness is significantly reduced. At present, there are many problems such as occurrence of phenomena.

In addition, the method of subjecting the coating layer on the film to electrical discharge machining also has a problem that, for example, simply making the surface hydrophilic makes the adhesiveness to an ultraviolet curable ink or the like worse. Poor versatility.

An object of the present invention is to provide a laminated polyester film which solves these drawbacks, has excellent adhesion to various coatings, and also has excellent adhesion after wet heat treatment, and a method for producing the same. Is what you do.

[0011]

According to the present invention, there is provided a laminated polyester film according to the present invention, wherein at least one surface of at least one surface of a polyester film is selected from acrylic resin, polyester resin and urethane resin.
There is a laminated film mainly composed of a kind of resin,
The laminated film is a film that has been subjected to electrical discharge machining in a nitrogen atmosphere, and has a water droplet contact angle of 50 degrees or more on the surface of the laminated film.

[0012] In this laminated polyester film, the laminated film is made of a resin mainly composed of an acrylic resin having a glass transition temperature of 0 to 50 ° C. A film formed from a resin composition containing a cross-linking agent in an amount of not less than 2 parts by weight and not more than 50 parts by weight in a partial weight ratio, and the polyester film is a polyethylene terephthalate film or a polyethylene-2,6-naphthalate film. There is a preferred embodiment.

In the method for producing a laminated polyester film of the present invention, at least one surface of the polyester film before the completion of the crystal orientation in the step of producing the polyester film is selected from an acrylic resin, a polyester resin and a urethane resin. After applying a coating liquid for forming a laminated film containing at least one kind of resin as a main component, the coating liquid is stretched in at least one direction and subjected to a heat treatment, and then the laminated film is subjected to electric discharge machining under a nitrogen atmosphere to obtain a surface of the laminated film. Characterized in that a laminated polyester film having a water droplet contact angle of 50 ° or more is produced, and a laminated film forming coating liquid has an acrylic resin having a glass transition temperature of 0 to 50 ° C. as a main component. A preferred embodiment is a liquid containing a resin as an active ingredient.

[0014]

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

In the polyester film referred to in the present invention, polyester is a generic name of polymers having an ester bond as a main bonding chain of a main chain. Preferred polyesters include ethylene terephthalate, propylene terephthalate, ethylene-2, 6-naphthalate, butylene terephthalate, propylene-2,6-naphthalate, ethylene-α, β-bis (2-chlorophenoxy)
Ethane-4,4'-dicarboxylate, ethylene-
Those having at least one component selected from α, β-bis (phenoxy) ethane-4,4′-dicarboxylate and the like as a main component can be used. One of these components may be used alone, or two or more of them may be used in combination. Among them, it is particularly preferable to use a polyester containing ethylene terephthalate as a main component when comprehensively judging quality, economy and the like. In addition, for example, when used in a portion close to a heating element such as a light source in an optical application, a field in which heat acts on a substrate, or an ultraviolet curable ink is used as a printing layer when performing various types of printing. Alternatively, in applications involving shrinkage of the resin during curing, such as providing an ultraviolet curable resin layer represented by a hard coat layer, polyethylene-2,6-naphthalate, which is excellent in heat resistance and rigidity, is more preferable.

Further, in these polyesters, other dicarboxylic acid components and diol components are partly, preferably, 2 or more.
0 mol% or less may be copolymerized.

Further, in the polyester, various additives such as antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers , An antistatic agent and a nucleating agent may be added to such an extent that their properties are not deteriorated.

The intrinsic viscosity of the above-mentioned polyester (25 ° C.
Measured in o-chlorophenol) is 0.4-1.2.
dl / g is preferable, and more preferably 0.5 to 0.8 d
Those in the range of 1 / g are suitable for practicing the present invention.

The polyester film using the above polyester is preferably biaxially oriented in a state where a laminated film is provided on at least one surface thereof. A biaxially oriented polyester film is generally a polyester sheet or film in an unstretched state stretched about 2.5 to 5 times in the longitudinal and width directions, and then subjected to a heat treatment to complete the crystal orientation. Which indicates a biaxially oriented pattern in wide-angle X-ray diffraction.

The thickness of the polyester film is not particularly limited, and is appropriately selected according to the application in which the laminated film of the present invention is used. However, it is usually preferable from the viewpoint of mechanical strength, handleability and the like. Is 1-500μ
m, more preferably 5 to 300 μm, most preferably 3
0 to 210 μm. Further, the obtained films can be used by being bonded by various methods.

In addition, for an image receiving sheet application, a label application, a recording card application, etc., a white polyester film can be suitably used as a base film.

The white polyester film is not particularly limited as long as it is a polyester film colored white, but the whiteness is preferably 65 to 150%, more preferably 80 to 120%. The concentration is preferably 0.5 to 5 in terms of 100 μm, more preferably 1 to 3. For example, when a base film having a small optical density is used, the concealing property is poor.For example, in a label or the like, the coloring of the application surface or the like is transmitted and the appearance of the printed layer on the surface is easily impaired, while the whiteness is low. If smaller,
Whiteness tends to decrease when viewed with the naked eye, which is not preferable as a white polyester film.

The method for obtaining such whiteness and optical density is not particularly limited, but can usually be obtained by adding a resin incompatible with inorganic particles or polyester. The amount to be added is not particularly limited, but is preferably 5 to 35% by weight, more preferably 8 to 2% in the case of inorganic particles.
5% by weight. On the other hand, when an incompatible resin is added, it is preferably 3 to 35% by volume, more preferably 6 to 2% by volume.
5% by volume.

The inorganic particles are not particularly limited, but preferably have an average particle size of 0.1 to 4 μm, more preferably 0.3 to 4 μm.
1.5 μm inorganic particles and the like can be used as typical examples. Specifically, barium sulfate, calcium carbonate, calcium sulfate, titanium oxide, silica, alumina, barium titanate, talc, clay and the like or a mixture thereof can be used.These inorganic particles are other inorganic compounds, for example, calcium phosphate. , Titanium oxide, mica, zirconia, tungsten oxide, lithium fluoride,
It may be used in combination with calcium fluoride or the like.

The resin incompatible with the above polyester is not particularly limited. For example, in the case of mixing with polyethylene terephthalate or polyethylene-2,6-naphthalate, acrylic resin, polyethylene, polypropylene, modified olefin resin And polybutylene terephthalate-based resin, phenoxy resin, polyphenylene oxide, and the like, and may be used in combination with the above-described inorganic particles. For example, in particular, polyester is mixed with inorganic particles or a resin incompatible with the polyester and biaxially stretched to have a cavity therein, and the specific gravity is 0.5 to
The 1.3 white polyester film has advantages that the base film itself can be reduced in weight, and when used for an image receiving sheet, the printing characteristics are improved.

This white polyester film is
A film colored in another color (the coloring method is not particularly limited, but usually a pigment or coloring is used), or a laminate of two or more layers in which a transparent film is laminated, and this is used as a substrate. It may be used as a film.

In the present invention, the term “laminated film” refers to a film-like film which is formed in a laminated structure on the surface of a polyester film as a substrate sheet. The laminated film itself may be a single layer or a multilayer.

In the present invention, the laminated film is made of an acrylic resin,
A film mainly composed of at least one resin selected from a polyester resin and a urethane resin, and the laminated film is a film that has been subjected to electric discharge machining in a nitrogen atmosphere, and furthermore, after the treatment, A water droplet contact angle on the surface of the laminated film is 50 degrees or more. As a resin constituting the laminated film, an acrylic resin, a polyester resin, and a urethane resin may be used alone, or two different resins, for example, a polyester resin and a urethane resin, a polyester resin and an acrylic resin, or A urethane resin and an acrylic resin may be used in combination, or three types may be used in combination.

In the laminated polyester film of the present invention, the polyester resin used as a component of the laminated film has an ester bond in a main chain or a side chain and is obtained by polycondensing a dicarboxylic acid and a diol. .

As the carboxylic acid component constituting the polyester resin, aromatic, aliphatic and alicyclic dicarboxylic acids and trivalent or higher polycarboxylic acids can be used.

As the aromatic dicarboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 2,5
-Dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bisphenoxyethane-p, p '
-Dicarboxylic acid, phenylindane dicarboxylic acid, and the like can be used. From the viewpoint of the strength and heat resistance of the laminated film,
These aromatic dicarboxylic acids are preferably at least 30 mol%, more preferably at least 35 mol% of the total dicarboxylic acid components.
As described above, it is most preferable to use a polyester occupying 40 mol% or more.

The aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, and 1,2-cyclohexane. Dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc.
And their ester-forming derivatives.

As the glycol component of the polyester resin, ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3
-Butanediol, 1,4-butanediol, 1,5-
Pentanediol, 1,6-hexanediol, 1,7
-Heptanediol, 1,8-octanediol, 1,
9-nonanediol, 1,10-decanediol, 2,
4-dimethyl-2-ethylhexane-1,3-diol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3 -Methyl-1,5
-Pentanediol, 2,2,4-trimethyl-1,6
-Hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-
Cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol, bisphenol A, 4,4′-methylenediphenol, 4,4 ′-(2 -Norbornylidene)
Diphenol, 4,4′-dihydroxybiphenol,
o-, m-, and p-dihydroxybenzene, 4,
4′-isopropylidenephenol, 4,4′-isopropylidenebindiol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol and the like can be used.

When the polyester resin is used as a coating liquid in the form of an aqueous liquid, a compound containing a sulfonate group or a compound containing a carboxylate group is used in order to easily make the polyester resin water-soluble or water-dispersible. Is preferably copolymerized.

Examples of the compound containing a carboxylate group include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid, ,
2,3,4-butanetetracarboxylic acid, 1,2,3,4
-Pentanetetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-cyclohexene-
1,2-dicarboxylic acid, cyclopentanetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid,
1,2,5,6-naphthalenetetracarboxylic acid, ethylene glycol bistrimellitate, 2,2 ', 3,3'
-Diphenyltetracarboxylic acid, thiophene-2,3
Examples thereof include 4,5-tetracarboxylic acid, ethylenetetracarboxylic acid, and the like, and alkali metal salts, alkaline earth metal salts, and ammonium salts thereof, but are not limited thereto.

Examples of the compound containing a sulfonate group include sulfoterephthalic acid, 5-sulfoisophthalic acid,
4-sulfoisophthalic acid, 4-sulfonaphthalene-2,
7-dicarboxylic acid, sulfo-p-xylylene glycol, 2-sulfo-1,4-bis (hydroxyethoxy)
Benzene or the like, or an alkali metal salt, an alkaline earth metal salt, or an ammonium salt thereof can be used, but is not limited thereto.

In the present invention, a modified polyester copolymer, for example, a block copolymer or a graft copolymer modified with acryl, urethane, epoxy or the like can be used as the polyester resin.

Preferred polyester resins include terephthalic acid, isophthalic acid, sebacic acid,
-Sodium sulfoisophthalic acid, ethylene glycol as a glycol component, diethylene glycol, 1,4
-A copolymer selected from butanediol and neopentyl glycol. If water resistance is required, instead of 5-sodium sulfoisophthalic acid,
Copolymers using trimellitic acid as a copolymer component thereof can also be suitably used.

In the laminated polyester film of the present invention, the polyester resin used for the laminated film can be produced by the following production method. For example, terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid as a dicarboxylic acid component, and ethylene glycol as a glycol component, a polyester resin composed of neopentyl glycol, terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid Ethylene glycol and neopentyl glycol are directly esterified, or terephthalic acid, isophthalic acid,
-A first step of transesterifying sodium sulfoisophthalic acid with ethylene glycol and neopentyl glycol, and a second step of subjecting the reaction product of the first step to a polycondensation reaction. it can.

At this time, as the reaction catalyst, for example, an alkali metal, an alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, a titanium compound and the like can be used.

As a method for obtaining a polyester resin having a large amount of carboxylic acid at the terminal and / or side chain,
JP-A-54-46294, JP-A-60-2090
No. 73, JP-A-62-240318, JP-A-53-26828, JP-A-53-26829, JP-A-53-98336, JP-A-56-11
No. 6,718, JP-A-61-124684, JP-A-62-240318, etc. can be produced with a resin obtained by copolymerizing a trivalent or higher polycarboxylic acid. It may be a method.

Further, the intrinsic viscosity of the polyester resin used for the laminated film according to the present invention is not particularly limited.
It is preferably at least 0.3 dl / g, more preferably at least 0.35 dl / g, most preferably at least 0.4 dl / g in terms of adhesiveness. Glass transition point of polyester resin (hereinafter abbreviated as "Tg")
Is preferably 0 to 130 ° C, more preferably 10 to 85 ° C. If the Tg is less than 0 ° C, for example, the heat-resistant adhesiveness is inferior, or a blocking phenomenon occurs in which the laminated films are fixed to each other. If the Tg exceeds 130 ° C, the stability and water dispersibility of the resin may be inferior. It is not preferable.

In the laminated polyester film of the present invention, the urethane resin used as a component of the laminated film is not particularly limited as long as it is a water-soluble or water-dispersible urethane resin having an anionic group. The component is obtained by copolymerizing a polyol compound and a polyisocyanate compound.

As the urethane resin, a urethane resin having an increased affinity for water by introducing a carboxylic acid group, a sulfonic acid group, or a sulfuric acid half ester base can be used. Carboxylates, sulfonates,
Alternatively, the content of the sulfuric acid half ester base or the like is 0.5 to 1
5% by weight is preferred.

Examples of the polyol compound include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene glycol, hexamethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5-pentanediol, diethylene glycol, and triethylene glycol. , Polycaprolactone, polyhexamethylene adipate, polytetramethylene adipate, trimethylolpropane, trimethylolethane, glycerin,
An acrylic polyol or the like can be used.

Examples of the polyisocyanate compound include tolylene diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, adducts of tolylene diisocyanate and trimethylolpropane, and adducts of hexamethylene diisocyanate and trimethylolethane. Can be used.

Here, the main constituent components of the urethane resin may contain a chain extender, a crosslinking agent and the like in addition to the polyol compound and the polyisocyanate compound.

As a chain extender or a crosslinking agent, ethylene glycol, propylene glycol, butanediol, diethylene glycol, ethylenediamine, diethylenetriamine and the like can be used.

The urethane resin having an anionic group is prepared by, for example, a method using a compound having an anionic group as a polyol, a polyisocyanate, a chain extender, or the like. It can be produced by a method of reacting a compound or a method of reacting a group having an active hydrogen of a urethane resin with a specific compound, but is not particularly limited.

The urethane resin having an anionic group includes a polyol having a molecular weight of 300 to 20,000, a polyisocyanate, a chain extender having a reactive hydrogen atom, a group which reacts with an isocyanate group, and at least one anionic group. Resins comprising a compound having two or more compounds are preferred.

The anionic group in the urethane resin is preferably used as a sulfonic acid group, a carboxylic acid group, or an ammonium salt, a lithium salt, a sodium salt, a potassium salt or a magnesium salt thereof.
It is a sulfonate group.

The amount of the anionic group in the polyurethane resin is preferably 0.05% by weight to 8% by weight. If the amount is less than 0.05% by weight, the water dispersibility of the urethane resin tends to be poor. If the amount exceeds 8% by weight, the water resistance and blocking resistance of the resin tend to be poor.

In the laminated polyester film of the present invention, the acrylic resin used as a component of the laminated film is, for example, an alkyl acrylate or an alkyl methacrylate (the alkyl group is a methyl group, an ethyl group) Group, n-
Propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.), 2-hydroxyethyl acrylate , 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, hydroxy group-containing monomers such as 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-
Amide group-containing monomers such as methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-phenylacrylamide, N, N-diethylaminoethyl acrylate, N , An amino group-containing monomer such as N-diethylaminoethyl methacrylate, an epoxy group-containing monomer such as glycidyl acrylate and glycidyl methacrylate, and a carboxyl group such as acrylic acid, methacrylic acid and salts thereof (lithium salt, sodium salt, potassium salt and the like). It is possible to use a monomer containing a salt thereof, and these are copolymerized using one kind or two or more kinds. Further, they can be used in combination with other types of monomers.

Here, other types of monomers include, for example,
Epoxy group-containing monomers such as allyl glycidyl ether, sulfonic acid groups such as styrene sulfonic acid, vinyl sulfonic acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.) or monomers containing a salt thereof, crotonic acid A monomer containing a carboxyl group or a salt thereof, such as, itaconic acid, maleic acid, fumaric acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.); acid anhydrides such as maleic anhydride, itaconic anhydride Monomer containing, vinyl isocyanate, allyl isocyanate,
Use styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane, alkyl maleate monoester, alkyl fumaric acid monoester, acrylonitrile, methacrylonitrile, alkyl itaconate monoester, vinylidene chloride, vinyl acetate, vinyl chloride, etc. be able to.

As the acrylic resin that can be used in the present invention, a modified acrylic copolymer, for example, a block copolymer or a graft copolymer modified with polyester, urethane, epoxy or the like can also be used.

The glass transition point (Tg) of the acrylic resin used in the present invention is not particularly limited, but is preferably -10 to 90 ° C, more preferably 0 to 5 ° C.
0 ° C, most preferably 10 to 40 ° C. When an acrylic resin having a low Tg is used, heat-resistant adhesiveness tends to be inferior or blocking tends to occur. On the other hand, when it is too high, adhesiveness deteriorates and film-forming properties deteriorate, which is not preferable. The molecular weight of the acrylic resin is preferably 50,000 or more, more preferably 300,000 or more, from the viewpoint of adhesiveness.

Preferred acrylic resins used in the present invention include copolymers selected from methyl methacrylate, ethyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-methylolacrylamide, and acrylic acid.

In the present invention, the acrylic resin is dissolved in water,
It is preferable to emulsify or suspend and use it as an aqueous acrylic resin liquid from the viewpoint of environmental pollution and explosion-proof property during coating.
Such an aqueous acrylic resin may be copolymerized with a monomer having a hydrophilic group (such as acrylic acid, methacrylic acid, acrylamide, vinyl sulfonic acid, or a salt thereof), emulsion-polymerized using a reactive emulsifier or a surfactant, and suspended. It can be prepared by a method such as turbid polymerization or soap-free polymerization.

In particular, it is preferable to use an acrylic resin for the laminated film in the present invention from the viewpoints of adhesion to various coatings and suppression of oligomers from the base polyester film. Further, in consideration of the adhesiveness with the base polyester film, it is also possible to suitably use an acrylic resin and a urethane resin, or to use an acrylic resin and a polyester resin in combination. In this case, the mixing ratio of both resins is arbitrarily selected. However, it is preferable that the acrylic resin is contained in a relatively large amount. In this case, the mixing ratio of the acrylic resin is preferably at least 60% by weight, more preferably at least 70% by weight.

Furthermore, surprisingly, a specific T
It has also been found that when an acrylic resin having a g is used, the contact angle of water droplets on the surface hardly changes even when the strength of the electric discharge machining treatment in a nitrogen atmosphere is increased. In general, when an electric discharge machining treatment is applied to a polyester film, the contact angle of water droplets on the surface decreases as the treatment intensity increases, so that the so-called hydrophilicity of the surface is promoted. As a result, the adhesiveness to various kinds of adherends is temporarily improved, and for example, the adhesiveness to a highly hydrophilic aqueous ink or the like is extremely improved. However, on the other hand, the adhesiveness with a hydrophobic coating, for example, an ultraviolet curable ink or the like is significantly reduced. According to the knowledge of the present inventors, a laminated film made of the above-described resin is provided on a polyester film. In this case, the water contact angle is 5
It has been found that when the angle is less than 0 degrees, the adhesiveness to the ink becomes extremely poor. In addition, the laminated film in the present invention needs to have a water droplet contact angle of 50 degrees or more, preferably 55 degrees or more, and more preferably 60 degrees or more, even after the electric discharge machining.

In the electric discharge machining process under a nitrogen atmosphere, increasing the treatment intensity means that more functional groups, such as amino groups and imino groups, generated and introduced into the laminated film are introduced. Is meant.

As described above, when an acrylic resin having a specific Tg is used, for example, from the viewpoint of manufacturing process control, even when the processing strength during electric discharge machining varies for some reason, the water droplet contact angle Hardly changes,
That is, since the degree of surface hydrophilicity hardly changes,
There are merits such as the influence on the adhesiveness change can be minimized.

According to the knowledge of the present inventors, the Tg of the acrylic resin is preferably from 0 to 50 ° C., more preferably from 10 to 40 ° C.

In the laminated film according to the present invention, when a crosslinking agent is added to at least one resin selected from an acrylic resin, a polyester resin, and a urethane resin from the viewpoint of adhesiveness, the laminated film under a nitrogen atmosphere can be used. A synergistic effect appears,
More preferred.

The crosslinking agent in the present invention is not particularly limited, but may be any of the functional groups present in the resins described above, such as a carboxyl group, a hydroxyl group, a methylol group,
Any compound capable of undergoing a crosslinking reaction with an amide group or the like may be used, for example, a melamine-based crosslinking agent, an oxazoline-based crosslinking agent, an isocyanate-based crosslinking agent, an aziridine-based crosslinking agent, an epoxy-based crosslinking agent, a methylolated or alkylolated urea-based crosslinking agent. Acrylamide-based, polyamide-based resin, amide-epoxy compound, various silane coupling agents, various titanate-based coupling agents, and the like. In particular,
Melamine-based cross-linking agents and oxazoline-based cross-linking agents can be suitably used from the viewpoint of compatibility with a resin, adhesion, and the like.

The melamine cross-linking agent used in the present invention is not particularly limited, but is partially or completely reacted by reacting a lower alcohol with melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, or a methylolated melamine. Etherified compounds or mixtures thereof can be used. In addition, as the melamine-based cross-linking agent, a monomer, a condensate composed of a multimer of a dimer or more, or a mixture thereof can be used. As the lower alcohol used for the etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like can be used. The functional group has an imino group, a methylol group, or an alkoxymethyl group such as a methoxymethyl group or a butoxymethyl group in one molecule, and includes an imino group-type methylated melamine resin, a methylol group-type melamine resin, and a methylol group-type. Methylated melamine resins, fully alkylated methylated melamine resins, and the like. Among them, an imino group type melamine resin and a methylolated melamine resin are preferable, and an imino group type melamine resin is most preferable. Further, an acidic catalyst such as p-toluenesulfonic acid may be used in order to promote the thermal curing of the melamine-based crosslinking agent.

The oxazoline crosslinking agent used in the present invention is not particularly limited as long as the compound has an oxazoline group as a functional group in the compound, and includes at least one monomer having an oxazoline group. It is preferable to use an oxazoline group-containing copolymer obtained by copolymerizing at least one other monomer.

Examples of the oxazoline group-containing monomer include 2-vinyl-2-oxazoline and 2-vinyl-4-
Methyl-2-oxazoline, 2-vinyl-5-methyl-
2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline and the like can be used. Mixtures of two or more can also be used. Among them, 2-isopropenyl-2-oxazoline is preferable because it is easily available industrially.

In the oxazoline-based crosslinking agent, the at least one other monomer used for the oxazoline group-containing monomer is not particularly limited as long as it is a monomer copolymerizable with the oxazoline group-containing monomer. However, for example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate,
Butyl acrylate, butyl methacrylate, acrylic acid-
Acrylates or methacrylates such as 2-ethylhexyl and 2-ethylhexyl methacrylate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid and maleic acid; acrylonitrile;
Unsaturated nitriles such as methacrylonitrile, unsaturated amides such as acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, vinyl esters such as vinyl acetate and vinyl propionate, methyl vinyl ether, ethyl vinyl ether and the like Vinyl ethers, olefins such as ethylene and propylene, halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride, and α, β-unsaturated aromatics such as styrene and α-methylstyrene. Group monomers and the like can be used, and these can be used alone or in combination of two or more.

In the laminated film according to the present invention, the resin and the cross-linking agent can be used in a mixture at any ratio.
In order to more remarkably exert the effects of the present invention, the crosslinking agent is
It is preferable to add 2 parts by weight or more and 50 parts by weight or less in terms of a solid content weight ratio to 100 parts by weight of the resin, and more preferably 3 to 25 parts by weight. The amount of crosslinking agent added is
When the addition is less than 2 parts by weight, the effect of the addition is small, and when it exceeds 50 parts by weight, the adhesiveness tends to decrease.

Various additives such as an antioxidant may be contained in the laminated film as long as the effects of the present invention are not impaired.
Heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, nucleating agents, and the like may be added.

In particular, those obtained by adding inorganic particles to the laminated film are more preferable because the lubricity and the blocking resistance are improved. In this case, as the inorganic particles to be added, silica,
Colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate and the like can be used. The inorganic particles used have an average particle size of 0.005.
To 5 μm, more preferably 0.01 to 3 μm
m, most preferably 0.05 to 2 μm, and the mixing ratio with respect to the resin in the laminated film is not particularly limited, but is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight in terms of solids weight ratio. Parts by weight.

In the production of the laminated polyester film of the present invention, a preferred method of providing a laminated film on the polyester film is to apply a laminated film forming coating solution on the substrate film during the production process of the polyester film. A method of stretching with a film is preferred. Among them,
In consideration of productivity, a method of providing a laminated film by a coating method during a film forming process is most preferable.

For example, the melt-extruded polyester film before crystal orientation is stretched about 2.5 to 5 times in the longitudinal direction, and a coating liquid is continuously applied to the uniaxially stretched film. The polyester film to which the coating liquid has been applied is dried while passing through a stepwise heated zone, and is stretched about 2.5 to 5 times in the width direction. Furthermore, continuously 150 ~
It can be obtained by a method (in-line coating method) of being guided to a heating zone at 250 ° C. and completing the crystal orientation.

In the present invention, before applying the coating liquid,
The surface of the base film (in the case of the above example, a uniaxially stretched polyester film) is subjected to a corona discharge treatment or the like, and the wet tension of the base film surface is preferably 47 mN / m.
As described above, more preferably 50 mN / m or more,
It is preferable because the adhesiveness of the laminated film to the base film can be improved.

The thickness of the laminated film is not particularly limited, but is usually preferably in the range of 0.01 to 5 μm, more preferably 0.02 to 2 μm, and most preferably 0.05 μm to
0.5 μm. If the thickness of the laminated film is too small, poor adhesion may occur.

Various coating methods such as a reverse coating method, a gravure coating method, a rod coating method, and the like can be applied to the coating liquid on the polyester film as the base film.
Bar coating method, Meyer bar coating method, die coating method,
A spray coating method or the like can be used.

In the present invention, it is necessary to perform electric discharge machining in a nitrogen atmosphere on the laminated film formed by coating, and a preferable method for the electric discharge machining is during the production process of the polyester film. The method of performing is preferred. Note that the nitrogen atmosphere may be an atmosphere in which a nitrogen-containing atom functional group can be effectively introduced into a treated surface by electric discharge machining, but the oxygen concentration is preferably 15% by volume or less, more preferably 10% by volume. Under the following atmosphere. When the oxygen concentration is high, the process becomes the same as that of ordinary electric discharge machining in air, and the functional groups derived from oxygen atoms tend to be selectively introduced to the treated surface.

The processing intensity of the electric discharge machining is as follows.
An “E value” defined by the following equation can be used.

E value = [(applied voltage) × (applied current)] /
[(Processing speed) × (electrode width)] Here, applied voltage (V), applied current (A), processing speed (m / s), and electrode width (m).

According to the knowledge of the present inventors, the E value can be appropriately selected within a range where the effect of the present invention is not impaired, but is preferably 300 to 70000 (W · s / m ² ). , More preferably 1000 to 25000 (W · s /
m ² ). If the treatment intensity is too weak, the effect of the electric discharge machining is hardly obtained, and if the treatment intensity is too strong, adverse effects such as excessively hydrophilizing the treated surface or damaging the treated surface are likely to occur.

Next, the method for producing a laminated polyester film of the present invention will be described with reference to an example in which polyethylene terephthalate (hereinafter abbreviated as “PET”) is used as a base film, but the present invention is not limited thereto.

The laminated film of the present invention, which has excellent adhesion even in various environments, comprises at least one surface of a polyester film containing at least one resin selected from an acrylic resin, a polyester resin and a urethane resin as a main component. Then, the laminated film is subjected to electric discharge machining in a nitrogen atmosphere, and the water droplet contact angle on the surface of the laminated film after the treatment is set to 50 ° or more.

More specifically, for example, the limiting viscosity is 0.5
After vacuum drying of ~ 0.8 dl / g PET pellets,
It is supplied to an extruder, melted at 260 to 300 ° C., extruded from a T-shaped die into a sheet, wound around a mirror casting drum having a surface temperature of 10 to 60 ° C. using an electrostatic application casting method, and cooled and solidified. Create an unstretched PET film. This unstretched film is stretched 2.5 to 5 times in the longitudinal direction (the direction of film movement) between rolls heated to 70 to 120 ° C. PET thus obtained
At least one surface of the film is subjected to a corona discharge treatment, the wet tension of the surface is set to 47 mN / m or more, and the coating liquid for forming a laminated film according to the present invention is applied to the treated surface. Next, the film coated with the coating liquid for forming a laminated film is gripped with a clip, guided to a hot-air zone heated to 70 to 150 ° C., dried, stretched 2.5 to 5 times in the width direction, and subsequently 160 to 150 μm.
It is led to a heat treatment zone of 250 ° C. and heat-treated for 1 to 30 seconds to complete the crystal orientation. During this heat treatment step, if necessary, 3 to 1 in the width direction or the longitudinal direction.
A 2% relaxation treatment may be applied. The biaxial stretching may be any of longitudinal and transverse sequential stretching or simultaneous biaxial stretching, and may be re-stretched in any of the longitudinal and transverse directions after the longitudinal and transverse stretching. The thickness of the polyester film is not particularly limited, but is preferably 1 to 500 μm.

Further, the above-mentioned polyester film is subjected to electric discharge machining in a nitrogen atmosphere.

In the above examples of the present invention, at least one component selected from a laminated film forming composition or a reaction product thereof can be contained in the base polyester film on which the laminated film is provided. in this case,
There are effects such as improvement in the adhesion between the laminated film and the base film, and improvement in the lubricity of the laminated film. Regarding the addition amount of the component, whether one kind or plural kinds, the total of the addition amount is 5 ppm or more and less than 20% by weight.
It is preferable in terms of lubricity. In view of environmental protection and productivity, a method using a regenerated pellet containing the laminated film-forming composition is preferable as a method for incorporating such a component into the base film.

In the laminated polyester film of the present invention thus obtained, various coatings such as various printing inks and ultraviolet curable resins can be provided on the laminated film. And since it can be made to have excellent adhesiveness to various coatings and also excellent adhesiveness after wet heat treatment, it can be widely used as a base film for various uses. For example, the laminated polyester film of the present invention is a label, an X-ray photographic film, a prepaid card such as a telephone card or a pachinko card, an optical film such as a diffusion plate, a prism film or an AR film, an optical recording card, an electrical insulating member, It can be used as a base film for a very wide range of uses such as magnetic tapes for audio, video, and computer, diazo films, and vapor-deposited films.

[Method of Measuring Characteristics and Method of Evaluating Effects]
The method for measuring characteristics and the method for evaluating effects in the present invention are as follows.

(1) Thickness of Laminated Film The thickness of the laminated film was determined from a photograph obtained by observing a cross section of the laminated polyester film provided with the laminated film using a transmission electron microscope HU-12 manufactured by Hitachi, Ltd. . The thickness was an average value of 30 pieces in the measurement visual field.

(2) Adhesion-1 (Adhesion under normal conditions) In order to evaluate the adhesion under normal conditions, the following four types of inks were used.

Ink A: "Best Cure" 161 Ink (T & K Toka Co., Ltd.) Ink B: "FLASH DRY" FD Carton P Ink (Toyo Ink Manufacturing Co., Ltd.) Ink C: Kuboi Ink Co., Ltd. HS ink (HS-
OS) ・ Ink D: Water-based ink (A manufactured by Arcar Graphics Inc.)
WK2-1 *) Here, the ink A and the ink B were applied on the laminated film to a thickness of about 1.5 μm by a roll coating method. Thereafter, irradiation was performed for 5 seconds at an irradiation distance (a distance between the lamp and the ink surface) of 9 cm using an ultraviolet lamp having an irradiation intensity of 80 W / cm to cure the ultraviolet curable ink. The evaluation of adhesion was performed by the following method.

100 cross-cuts of 1 mm ² were put in the cured film of the ultraviolet-curable ink, and cellophane tape manufactured by Nichiban Co., Ltd. was adhered thereon, and a rubber roller was used.
After reciprocating three times under a load of 19.6 N, pressing, and peeling in the direction of 90 degrees, a four-level evaluation was performed based on the number of remaining cured films (A: 100, B: 80 to 99, B: 50 to 79, X:
0-49). (◎) and (○) were evaluated as having good adhesiveness.

The ink C was applied to a thickness of about 1.5 μm on the laminated film by a roll coating method. Then, it was left to cure under normal conditions for 24 hours. The evaluation of the adhesiveness was performed by the same method as the method for the ultraviolet curable ink described above.

Regarding the ink D, the ink was applied on the laminated film to a thickness of about 2 μm by a gravure coating method, and dried by heating in a hot air oven at 120 ° C. for 2 minutes. The evaluation of the adhesiveness was performed by the same method as the method for the ultraviolet curable ink described above.

(3) Humidity and heat resistance In the same manner as in (2) above, after a layer obtained by curing an ultraviolet curable ink was provided on the laminated film, the film was subjected to 40 ° C. and 90% relative humidity.
For 24 hours, the same adhesive evaluation as in the above (2) was performed. UV-curable inks are available from T &
K Besta 161 black ink manufactured by Toka Corporation was used.

(4) Contact Angle of Water Drop After leaving for 24 hours in a normal state (23 ° C., 65% relative humidity), a contact angle meter CA-D (manufactured by Kyowa Interface Science Co., Ltd.) was used under the same atmosphere. The contact angle was measured using distilled water stored under the conditions. The measurement used the average value of ten pieces.

(5) Glass transition temperature (Tg) A robot DSC (differential scanning calorimeter) RDC220 manufactured by Seiko Denshi Kogyo Co., Ltd.
The measurement was performed with a 5200 disk station connected. D
The measurement conditions of SC are as follows. That is, the sample 10m
After adjusting g in an aluminum pan, it is set in a DSC apparatus (reference: an aluminum pan of the same type without a sample), heated at a temperature of 300 ° C. for 5 minutes, and then quenched in liquid nitrogen. This sample was heated at 10 ° C /
And the glass transition point (T
g) is detected.

(6) Oligomer Inhibition After heating the laminated film in an oven at 170 ° C. for 10 minutes, the surface of the laminated film was scanned with a scanning electron microscope (S-210).
Using a 0A type Hitachi scanning electron microscope (Hitachi, Ltd.) at a magnification of 3000 times, the degree of oligomer precipitation was visually inspected, and the following three-step evaluation was performed.

Those where almost no oligomer precipitation was observed: 3 Some oligomer precipitation, but no practical problems: 2 Those where oligomer precipitation was remarkable: 1

[0100]

EXAMPLES Next, the present invention will be described based on examples, but the present invention is not necessarily limited to these.

Example 1 PET pellets containing 0.015% by weight of colloidal silica having an average particle size of 0.4 μm and 0.005% by weight of colloidal silica having an average particle size of 1.4 μm (intrinsic viscosity 0.63 dl / g) was sufficiently dried in a vacuum, fed to an extruder, melted at 285 ° C., extruded into a sheet shape from a T-shaped die, and wound around a mirror casting drum having a surface temperature of 25 ° C. using an electrostatic application casting method. After cooling and solidification, an unstretched film was obtained. This unstretched film is heated to 90 ° C. and stretched 3.3 times in the longitudinal direction,
A uniaxially stretched film (substrate PET film) was used. This substrate PET film is subjected to corona discharge treatment in air,
The wet tension of the uniaxially stretched base PET film is 55 mN
/ M, and a coating liquid for forming a laminated film having the following composition was applied to the treated surface. Next, the uniaxially stretched film coated with the coating liquid for forming a laminated film was guided to a preheating zone while being gripped with a clip, and 9
After drying at 0 ° C., the film was continuously stretched 3.5 times in the width direction in a heating zone at 105 ° C., and further subjected to a heat treatment in a heating zone at 230 ° C. to obtain a laminated PET film in which crystal orientation was completed. At this time, after the heat treatment step, electric discharge machining was performed in a nitrogen atmosphere. The E value is 3600 (W ·
s / m ² ), the thickness of the base PET film was 50 μm, and the thickness of the laminated film was 0.1 μm. Table 1 shows the results.

"Laminated film forming coating liquid" The following polyester resin-1 and polyester resin-2 were mixed at a solid content weight ratio of 50%.
/ 50 parts by weight of the melamine-based cross-linking agent was added to 100 parts by weight of the mixture to give a laminated film forming coating liquid. Polyester resin (Polyester resin 1): Acid component Terephthalic acid 50 mol% Isophthalic acid 29 mol% Sebacic acid 20 mol% 5-Sodium sulfoisophthalic acid 1 mol% Diol component ethylene glycol 55 mol% neopentyl glycol 44.5 Mol% polyethylene glycol (molecular weight: 4000) 0.5
Mol% An aqueous dispersion of a polyester resin (Tg: 4 ° C.) comprising the acid component and the diol component. -Polyester resin (Polyester resin 2):-Acid component 88% by mole of terephthalic acid 12% by mole of 5-sodium sulfoisophthalic acid-Diol component 98% by mole of ethylene glycol 2% by mole of diethylene glycol Polyester resin (Tg) comprising the above acid component and diol component : 81 ° C). Melamine-based cross-linking agent: a coating liquid obtained by diluting methylolated melamine in a mixed solvent (10/90 (weight ratio)) of isopropyl alcohol and water.

Comparative Example 1 A laminated PET was produced in the same manner as in Example 1 except that the electric discharge machining was not performed.
A film was obtained. Table 1 shows the results.

(Example 2) The same procedure as in Example 1 was repeated except that the coating liquid for forming a laminated film was changed to the following composition.
An ET film was obtained. Table 1 shows the results.

"Coating solution for forming a laminated film" Acrylic resin: (Acrylic resin 1) Methyl methacrylate 60% by weight Ethyl acrylate 37% by weight Acrylic acid 2% by weight N-methylolacrylamide 1% by weight Acrylic resin copolymerized with the above composition Polymer (Tg: 4
2 ° C.) aqueous emulsion.

Comparative Example 2 A laminated PET was produced in the same manner as in Example 2 except that the electric discharge machining was not performed.
A film was obtained. Table 1 shows the results.

Example 3 Example 1 was the same as Example 1 except that the coating liquid for forming a laminated film had the following composition and the treatment strength E value of the electric discharge machining was 1200 (W · s / m ² ). Similarly, a laminated PET film was obtained. Table 1 shows the results.

"Laminated film forming coating liquid" Acrylic resin 1 described below
A coating liquid for forming a laminated film was prepared by adding 10 parts by weight of an oxazoline-based crosslinking agent at a solid content weight ratio to 00 parts by weight. Acrylic resin: (Acrylic resin 2) Methyl methacrylate 50% by weight Ethyl acrylate 47% by weight Acrylic acid 1% by weight N-methylolacrylamide 1% by weight Acrylonitrile 1% by weight Acrylic resin copolymer (Tg: 3) copolymerized with the above composition
5 ° C.) aqueous emulsion. Oxazoline-based crosslinking agent: "Epocross" WS-500 manufactured by Nippon Shokubai Co., Ltd.

(Example 4) In Example 3, the E value was set to 2100.
A laminated PET film was obtained in the same manner as in Example 3 except that (W · s / m ² ) was used. Table 1 shows the results. (Example 5) In Example 3, the E value was changed to 3600 (W · s / m
^A laminated PET film was obtained in the same manner as in Example 3 except that ² ) was used. Table 1 shows the results.

(Example 6) In Example 3, the E value was set to 7200.
A laminated PET film was obtained in the same manner as in Example 3 except that (W · s / m ² ) was used. Table 1 shows the results.

Comparative Example 3 A laminated PET was produced in the same manner as in Example 3 except that the electric discharge machining was not performed.
A film was obtained. Table 1 shows the results.

Example 7 Example 1 was repeated except that the coating liquid for forming the laminated film had the following composition and the treatment strength E value of the electric discharge machining was 7200 (W · s / m ² ). Similarly, a laminated PET film was obtained. Table 1 shows the results.

"Laminated film forming coating solution" Acrylic resin 1 described below
A coating liquid for forming a laminated film was prepared by adding 20 parts by weight of a melamine-based cross-linking agent at a solid content weight ratio with respect to 00 parts by weight. Acrylic resin: (Acrylic resin 3) Methyl methacrylate 40% by weight Ethyl acrylate 57% by weight Acrylic acid 2% by weight N-methylolacrylamide 1% by weight Acrylic resin copolymer (Tg: 2) copolymerized with the above composition
0 ° C.) aqueous emulsion. Melamine-based cross-linking agent: a mixed solvent (10/90 (weight ratio)) of "Symel" 325 (imino group type methylated melamine) manufactured by Mitsui Cyanamid Co., Ltd., which is a high solid type amino resin, with isopropyl alcohol and water. Coating solution diluted in

(Example 8) In Example 7, the E value was set to 3000.
A laminated PET film was obtained in the same manner as in Example 7, except that 0 (W · s / m ² ) was used. Table 1 shows the results.

(Example 9) Example 1 was repeated except that the coating liquid for forming a laminated film had the following composition and the treatment strength E value of the electric discharge machining was 3600 (W · s / m ² ). Similarly, a laminated PET film was obtained. Table 1 shows the results.

"Laminated film forming coating liquid" Acrylic resin 6 described below
A coating liquid for forming a laminated film was prepared by adding 10 parts by weight of a melamine-based crosslinking agent at a solid content weight ratio to 0 parts by weight and 40 parts by weight of a polyester resin. Acrylic resin: (Acrylic resin 3) Methyl methacrylate 40% by weight Ethyl acrylate 57% by weight Acrylic acid 2% by weight N-methylolacrylamide 1% by weight Acrylic resin copolymer (Tg: 2) copolymerized with the above composition
0 ° C.) aqueous emulsion.・ Polyester resin: (Polyester resin 3) ・ Acid component Terephthalic acid 60 mol% Isophthalic acid 14 mol% Sebacic acid 6 mol% Trimellitic acid 20 mol% ・ Diol component Ethylene glycol 28 mol% Neopentyl glycol 38 mol% 1,4 -Butanediol 34 mol% An aqueous dispersion in which a polyester resin (Tg: 20 ° C) comprising the above acid component and diol component is made aqueous with aqueous ammonia. Melamine-based cross-linking agent: a mixed solvent (10/90 (weight ratio)) of "Symel" 325 (imino group type methylated melamine) manufactured by Mitsui Cyanamid Co., Ltd., which is a high solid type amino resin, with isopropyl alcohol and water. Coating solution diluted in

Example 10 Example 1 was repeated except that the coating liquid for forming a laminated film had the following composition and the treatment strength E value of the electric discharge machining was 2100 (W · s / m ² ). Similarly, a laminated PET film was obtained. Table 1 shows the results.

"Laminated film forming coating liquid" Urethane resin 1 described below
A coating liquid for forming a laminated film was prepared by adding 5 parts by weight of a melamine-based cross-linking agent at a solid content weight ratio to 00 parts by weight. -Urethane resin: "Hydran" manufactured by Dainippon Ink Industries, Ltd., which is an aqueous coating of an ionomer-type aqueous urethane resin
AP-10 was used. Melamine-based cross-linking agent: a coating liquid obtained by diluting methylolated melamine in a mixed solvent (10/90 (weight ratio)) of isopropyl alcohol and water.

(Embodiment 11) In Embodiment 5, the PET
A laminated PEN was prepared in the same manner as in Example 5 except that pellets were replaced with polyethylene-2,6-naphthalate (hereinafter abbreviated as “PEN”) pellets and PEN films were used.
A film was obtained. Table 1 shows the results.

Example 12 PET pellets containing 5% by weight of polymethylpentene (intrinsic viscosity 0.63 dl)
/ G) was sufficiently vacuum-dried and then supplied to an extruder A heated to 280 ° C. 7% by weight of titanium oxide
Finely dispersed PET pellets (intrinsic viscosity 0.63 dl /
After g) was sufficiently dried in vacuum, it was supplied to an extruder B heated to 285 ° C. The polymers extruded from the extruders A and B are laminated by co-extrusion so as to form a three-layer structure of B / A / B, extruded into a sheet shape from a T-shaped die, and the surface is applied using an electrostatic application casting method. It was wound around a mirror casting drum at a temperature of 20 ° C. and solidified by cooling to obtain an unstretched film.

The unstretched film thus obtained was heated to 90 ° C. and stretched 3.4 times in the longitudinal direction to obtain a uniaxially stretched film. The uniaxially stretched film is subjected to a corona discharge treatment in air to reduce the wetting tension of the base film to 55.
mN / m, and the same coating liquid for forming a laminated film as in Example 5 was applied to the treated surface. While holding the uniaxially stretched film coated with the coating liquid for forming a laminated film with a clip, the film is guided to a preheating zone.
After drying at 0 ° C., the film was continuously stretched 3.4 times in the width direction in a heating zone at 105 ° C., and further subjected to a heat treatment in a heating zone at 210 ° C. to obtain a laminated PET film in which crystal orientation was completed. At this time, after the heat treatment step, electric discharge machining was performed in a nitrogen atmosphere. The E value is 3600 (W ·
s / m ² ), the thickness of the base PET film is 50 μm (the thickness ratio is B / A / B = 5/90/5), and the thickness of the laminated film is 0.1 μm.
It was 1 μm.

Table 1 shows the results. Since the film has fine cavities, there are many advantages such as extremely good handling properties and printing properties, and reduction in weight.

(Comparative Example 4) In Example 1, the E value was 30,000 (W)
A PET film was obtained in the same manner as in Example 1 except that electric discharge machining was performed in a nitrogen atmosphere at a rate of s / m2). Table 1 shows the results.

(Comparative Example 5) In Example 1, the electric discharge machining treatment in air was carried out in which the coating liquid for forming the laminated film had the following composition, and the treatment intensity E value of the electric discharge machining treatment was 30,000 (W · s / m ² ). Except that the laminated PET was used in the same manner as in Example 1.
A film was obtained. Table 1 shows the results.

"Laminated film forming coating liquid" Polyester resin: (Polyester resin 4) Acid component Terephthalic acid 58 mol% Isophthalic acid 37 mol% 5-Sodium isophthalic acid 5 mol% Diol component Ethylene glycol 60 mol% 1, 4-butanediol 40 mol% An aqueous coating liquid of a polyester resin (Tg: 50 ° C.) comprising the above acid component and diol component.

[0126]

[Table 1]

[0127]

The polyester film having a laminated film according to the present invention can be used with various coating materials such as aqueous inks, ultraviolet curable inks, general dry inks, aqueous paints, non-aqueous paints, and ultraviolet curable resins for forming a hard coat layer. Has excellent adhesiveness, and also has excellent adhesiveness after wet heat treatment.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B32B 27/40 B32B 27/40 C08J 7/00 CFD C08J 7/00 CFDZ 303 303 // B29K 67:00 B29K 67:00 B29L 7:00 B29L 7:00 9:00 9:00 C08L 67:00 C08L 67:00 F term (reference) 4D075 BB07Y BB25Y BB44Z BB49Z BB52Z CA13 CA37 DA04 DB48 DC24 DC27 DC38 EA06 EA07 EA10 EB22 EB32 EB33 EB35 EB35 EB38 EB45 EB53 EB56 4F073 AA01 BA23 BA24 BB01 CA21 CA63 4F100 AA20H AK25B AK25C AK41A AK41B AK41C AK42B AK42C AK51B AK51C BA02 BA03 BA06 BA10B BA10C CA02B CA02C CA23 EH462 EJ372 EJ412 EJ55B EJ55C EJ552 EJ60B EJ60C EJ602 GB15 GB41 JA05B JA05C JB05B JB05C JL11 YY00B YY00C 4F210 AA21 AA24 AA26 AA31 AG01 AG03 QC01 QC05 QG01 QG15 QG18 QW34

Claims (6)

[Claims] 1. A laminated film mainly comprising at least one resin selected from an acrylic resin, a polyester resin and a urethane resin on at least one surface of a polyester film, and the laminated film is formed under a nitrogen atmosphere. A laminated polyester film which is a film subjected to electric discharge machining and has a water droplet contact angle of 50 ° or more on the surface of the laminated film. 2. The laminated film has a glass transition temperature of 0 to 50 ° C.
The laminated polyester film according to claim 1, comprising a resin containing an acrylic resin as a main component. 3. The laminated film is a film formed from a resin composition containing 2 to 50 parts by weight of a cross-linking agent in a solid content ratio by weight to 100 parts by weight of a resin component. The laminated polyester film according to claim 1 or 2, wherein: 4. The polyester film is a polyethylene terephthalate film or polyethylene-2,6-
The laminated polyester film according to claim 1, 2 or 3, which is a naphthalate film. 5. At least one resin selected from an acrylic resin, a polyester resin and a urethane resin is a main component on at least one surface of the polyester film before crystal orientation is completed in the process of producing the polyester film. After applying the coating liquid for forming a laminated film, the film is stretched in at least one direction and subjected to a heat treatment. Thereafter, the laminated film is subjected to electric discharge machining under a nitrogen atmosphere, and the contact angle of a water droplet on the surface of the laminated film is 50 degrees or more. A method for producing a laminated polyester film, which comprises producing a polyester film. 6. The coating liquid for forming a laminated film has a glass transition temperature of 0.
6. A liquid containing, as an active ingredient, a resin mainly composed of an acrylic resin at a temperature of 50 to 50 [deg.] C.
3. The method for producing a laminated polyester film according to item 1.