JP2001301108A - Laminated polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated polyester film capable of satisfying adhesiveness with an ink receiving layer in ink jet printing and water resistance. SOLUTION: The laminated polyester film is constituted by forming a coating layer, which comprises a composition prepared by mixing an aqueous polyester resin and a hydroxyl group-containing vinyl type resin. The hydroxyl number is 30-80 mgKOH/g, in a solid weight ratio of 50/50-85/15 on at least the single surface of a polyester film. The ink receiving layer can be further provided on the coating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated polyester film, and more particularly to a laminated polyester film capable of satisfying adhesiveness to an ink receiving layer and water resistance in ink jet printing.

[0002]

2. Description of the Related Art As a method of performing recording using a recording liquid, an ink jet recording system has recently emerged.
Ink-jet recording is a method in which small droplets of a recording liquid are generated according to various operating principles, and the droplets are made to fly and adhere to a recording material such as paper, thereby performing recording. It is attracting attention as a recording method that can generate high-speed and multicolor printing with less occurrence. As a recording liquid for ink jet recording, an aqueous recording liquid is mainly used from the viewpoint of safety and printability.

Conventionally, ordinary paper has been generally used as a recording material used in the ink jet recording method. However, with the improvement of the performance of the ink jet recording machine, such as high-speed recording or multi-color recording, more advanced characteristics are also required for the recording material for ink jet recording.

That is, in order to obtain high-resolution and high-quality recording image quality, there has been proposed an ink-jet recording material having high ink absorbency and excellent coloring properties. For example, an ink-jet recording material having an ink-receiving layer using various water-absorbing organic materials or inorganic materials containing pseudo-boehmite as a main component (Japanese Patent Application Laid-Open No. Hei 3-215082).

On the other hand, biaxially oriented polyester films are:
Because of its excellent properties such as dimensional stability, mechanical properties, heat resistance, transparency and electrical properties, it can be used in many applications such as magnetic recording materials, packaging materials, electrical insulating materials, various photographic materials and graphic arts materials. Widely used as a base film.

In general, biaxially oriented polyester films have a highly crystallized surface, so that various paints and resins,
It has the disadvantage of poor adhesion to ink. For this reason, conventionally, studies have been made to impart adhesiveness to the polyester film surface by various methods.

Conventionally, methods for imparting adhesiveness to a polyester film include, for example, a surface activation method in which the surface of a polyester film as a substrate is subjected to a corona discharge treatment, an ultraviolet irradiation treatment, a plasma treatment, or the like, an acid, an alkali or an amine. A surface etching method using a chemical such as an aqueous solution, a method of providing various resins such as an acrylic resin, a polyester resin, a urethane resin or a polyolefin resin on a film surface as a primer layer, and the like are known (Japanese Patent Application Laid-Open No. 58-29626, JP-A-60-
149442, JP-A-62-152850 and JP-A-1-108037).

[0008]

However, the above-mentioned conventional polyester film still has a problem that the adhesion to the ink receiving layer in ink jet printing is insufficient. An object of the present invention is to improve the disadvantages of the prior art and to provide a laminated polyester film capable of satisfying the adhesiveness to an ink receiving layer and the water resistance in ink jet printing.

[0009]

According to the present invention, there is provided a laminated polyester film according to the present invention, wherein an aqueous polyester resin and a hydroxyl group-containing vinyl resin are coated on at least one surface of the polyester film in a solid content weight ratio of 50/50.
A coating layer formed by mixing at a ratio of 85 to 15 was formed, and the hydroxyl value of the vinyl resin was 30 to 80 mgK.
OH / g is a laminated polyester film.

In the laminated polyester film of the present invention, it is preferable that an ink receiving layer is further formed on the coating layer. The laminated polyester film of the present invention thus prepared is suitable for inkjet printing. Used for

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the laminated polyester film of the present invention, the polyester constituting the polyester film is a general term for a polymer compound having an ester bond as a main bonding chain of a main chain. Ethylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, ethylene-α,
β-bis (2-chlorophenoxy) ethane-4,4′-
Those having at least one component selected from 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. When heat acts on the polyester film, it is preferable to use polyethylene-2,6-naphthalate having excellent heat resistance and rigidity.

Further, in these polyesters, other dicarboxylic acid components and diol components are partially contained, preferably 2
0 mol% or less may be copolymerized. Furthermore, in this polyester, various additives, for example, antioxidants, 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 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
Polyesters in the 1 / g range are preferred in practicing the present invention.

The polyester film using the above polyester is preferably biaxially oriented after the application layer is provided. A biaxially oriented polyester film generally means that an unstretched polyester sheet or film is stretched usually about 2.5 to 5 times each in the longitudinal direction and the width direction, and then subjected to heat treatment to complete crystal orientation. And shows a biaxially oriented pattern in wide-angle X-ray diffraction.

[0015] The thickness of the polyester film used in the present invention is not particularly limited and may be appropriately selected.
５００500 μm, preferably 5-300 μm. Further, the obtained films can be used by being bonded by various methods.

As the polyester film of the present invention, a white polyester film is suitably used in addition to a transparent polyester film. The white polyester film is not particularly limited as long as it is a polyester film colored white, and preferably has a whiteness of 85 to 150%, more preferably 90 to 1%.
30%, and the optical density is preferably 0.5 to 5,
More preferably, it is the case of 1-3. For example, when using a polyester film of a substrate having a small whiteness,
The pattern and coloring on the opposite side are easily transmitted and the appearance of the printed layer on the surface is easily impaired.On the other hand, when the optical density is low, sufficient light reflection is not obtained, and whiteness decreases when viewed with the naked eye. It is not preferable because it is affected by the surface.

The method for obtaining such optical density and whiteness is not particularly limited, but can usually be obtained by adding a resin incompatible with inorganic particles or polyester. The amount of these added is not particularly limited, but is preferably 3 to 35% by weight, more preferably 5 to 25% by weight in the case of inorganic particles. When an incompatible resin is added, the content is preferably 3 to 35% by volume, more preferably 5 to 25% 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.
Inorganic particles of up to 1.5 μm can be used as typical examples. As the inorganic particles, specifically, barium sulfate, calcium carbonate, calcium sulfate, titanium oxide, silica, alumina, talc, clay and the like or a mixture thereof can be used.These inorganic particles are other inorganic compounds such as calcium phosphate, Titanium oxide, mica,
It may be used in combination with zirconia, tungsten oxide, lithium fluoride, calcium fluoride and the like. When inorganic particles having a Mohs hardness of 5 or less, preferably 4 or less are used among the above-mentioned inorganic particles, it is more preferable because the whiteness is further increased.

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 Polybutylene terephthalate resin, phenoxy resin, polyphenylene oxide, or the like can be used, and may be used in combination with the above-described inorganic particles. For example, in particular, a white polyester film having a specific gravity of about 0.5 to 1.5, in which a resin mixed with a resin incompatible with inorganic particles or polyester and biaxially stretched and having a cavity therein, has good printing characteristics. Is preferred.

In the laminated polyester film of the present invention, an aqueous polyester resin and a vinyl resin having a hydroxyl group are provided on at least one surface of the polyester film as a base material at a solid content weight ratio of 50/50 to 85/15. A coating layer formed by mixing is formed, and the solid content weight ratio is more preferably 70/30 to 80/20. When the solid content weight ratio is out of this range, when the amount of the aqueous polyester resin is small, the adhesion or water resistance to the base polyester film is insufficient, and when the amount of the vinyl resin is small, the adhesion to the ink receiving layer is insufficient. Or insufficient water resistance.

The aqueous polyester resin used in the coating layer according to the present invention is not particularly limited as long as it shows water solubility and / or water dispersibility and has an ester bond in a main chain or a side chain. It can be obtained by polycondensation from the component and the glycol component.

As the acid component constituting the aqueous polyester resin, terephthalic acid, isophthalic acid, phthalic acid, 2,2
5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bisphenoxyethane-p,
p'-dicarboxylic acid, phenylindanedicarboxylic acid,
Succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid,
1,4-Cyclohexanedicarboxylic acid and the like, and their ester-forming derivatives can be used, but are not limited thereto.

By introducing a sulfonic acid group and a sulfonic acid group, water can be imparted to the polyester resin. As an acid component containing the group, for example, sulfoterephthalic acid, 5-sulfoisophthalic acid, Alkali metal salts and alkaline earth metal salts such as -sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, sulfo-p-xylylene glycol, and 2-sulfo-1,4-bis (hydroxyethoxy) benzene , Ammonium salts and the like can be used, but the present invention is not limited thereto.

Further, by introducing a carboxylic acid group and a carboxylic acid group, water can be imparted to the polyester resin, and as an acid component containing the group, for example, trimellitic acid, trimellitic anhydride, pyromellitic acid, etc. Acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,2
3-tricarboxylic acid, trimesic acid, 1,2,3,4-
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, 1,2,2
5,6-naphthalenetetracarboxylic acid, ethylene glycol bistrimellitate, 2,2 ', 3,3'-diphenyltetracarboxylic acid, thiophene-2,3,4,5-
Alkali metal salts such as tetracarboxylic acid and ethylenetetracarboxylic acid, alkaline earth metal salts, and ammonium salts can be used, but the present invention is not limited thereto.

The glycol components constituting the aqueous polyester resin include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol and 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,
-Methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, ,
2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol, bisphenol A, 4,4′-methylenediphenol, 4,4 ′-(2
-Norbornylidene) diphenol, o-, m-, and p-dihydroxybenzene, p, p'-isopropylidenediphenol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4 -Diols and the like can be used, but the present invention is not limited thereto.

The vinyl resin used for the coating layer according to the present invention is a vinyl resin containing a hydroxyl group, and is not particularly limited as long as the vinyl resin has a hydroxyl value of 30 to 80 mgKOH / g. No, but the hydroxyl value is 4
More preferably, it is 0 to 60 mgKOH / g.
If the hydroxyl value is outside this range, the adhesiveness and water resistance will be poor.

As a monomer component constituting the vinyl resin, in particular, as a monomer having a hydroxyl group, for example,
2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, etc. However, the present invention is not limited to these, as a copolymer component,
It is also possible to use completely or partially saponified polyvinyl alcohol and its anion, cation modified product, polyvinyl alcohol having a degree of acetalization or butyralization of 30% or less, and the method of introducing a hydroxyl group is not limited to these methods. It is not something to be done.

Examples of other monomers constituting the vinyl resin include, but are not particularly limited to, alkyl acrylates and alkyl methacrylates (where the alkyl group is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n- Butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.), acrylamide, methacrylamide, N-methylacrylamide, N-methyl Methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-phenylacrylamide, N-vinylacetamide Amide group-containing monomers such as bromide, N, N-diethylaminoethyl acrylate, N,
Amino group-containing monomers such as N-diethylaminoethyl methacrylate, epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof ( Monomers containing a carboxyl group or a salt thereof such as lithium salt, sodium salt, potassium salt, ammonium salt), monomers containing an acid anhydride such as maleic anhydride, itaconic anhydride, styrenesulfonic acid, vinylsulfonic acid and Their salts (lithium salts,
As a monomer containing a sulfonic acid group or a salt thereof such as a sodium salt, a potassium salt, and an ammonium salt, and other types of monomers, although not particularly limited, for example, vinyl isocyanate, allyl isocyanate, ethylene, styrene, and vinylmethyl Ether, vinylethyl ether, vinyltrisalkoxysilane, alkylmaleic acid monoester, alkylfumaric acid monoester, acrylonitrile, methacrylonitrile, alkylitaconic acid monoester, vinylidene chloride, vinyl acetate, vinyl chloride, polyvinylpyrrolidone, polyethylene oxide, Ethylene oxide-propylene oxide copolymer, polybutylene oxide, carboxylated polyethylene oxide and the like can be used. It is copolymerized with the above. Further, it can be used in combination with a modified copolymer (block copolymer, graft copolymer, etc.).

The coating layer according to the present invention may contain another resin, for example, a modified polyester copolymer (for example, a block modified with acryl, urethane, epoxy, etc.) as long as the effects of the present invention are not impaired. Copolymers, graft copolymers, etc.), acrylic resins, urethane resins, epoxy resins, polycarbonate resins, silicone resins, alkyd resins, urea resins and phenolic resins, and water-soluble resins described below as resins contained in the ink receiving layer. And / or a water-dispersible resin. Furthermore, in the coating layer according to the present invention, various additives such as an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, a lubricant, and a pigment, as long as the effects of the present invention are not impaired. , A dye, organic or inorganic fine particles, a filler, an antistatic agent and a nucleating agent.

It is optional to add particles to the coating layer according to the present invention. However, the addition of these particles is preferable because the lubricity, blocking resistance, and adhesion to the ink receiving layer are improved. . The particles are not particularly limited, but silica, colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate and the like can be used. The average particle size of the particles is not particularly limited, but is preferably 0.01 to 5 μm, and more preferably 0.04 to 3 μm. The mixing ratio of the particles to the total resin in the coating layer is not particularly limited, but is preferably 0.05 to 8 parts by weight, more preferably 0.1 to 3 parts by weight in terms of solids weight ratio.

The thickness of the coating layer according to the present invention is not particularly limited, but is preferably 0.02 to 5 μm, more preferably 0.03 to 2 μm, and most preferably 0.05 to 0.05 μm.
０．５0.5 μm. If the thickness of the layer is too small, the adhesion to the ink receiving layer and the water resistance may be poor.

The method for forming the above-mentioned coating layer on a polyester film as a substrate is not particularly limited, but various coating methods such as a reverse coating method, a gravure coating method, a rod coating method, a bar coating method, Die coating and spray coating can be used. Preferably, a method of applying a resin dissolved and dispersed in an organic solvent or water is used in the production process of the polyester film. In the laminated polyester film of the present invention, an ink receiving layer can be further formed on the coating layer. The ink receiving layer formed on the coating layer contains a water-soluble resin and / or a water-dispersible resin, and is not particularly limited as long as it absorbs the ink for inkjet. Examples of the water-soluble resin and / or water-dispersible resin include methyl cellulose, hydroxyethyl cellulose,
Carboxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylethyl cellulose, cellulose sulfate, potato starch, potato starch, oxidized starch, phosphate starch, carboxylated starch, hydroxyethylated starch, cyanoethylated starch, acrylic acid grafted starch, dextrin, corn starch, konjac , Seaweed, agar, sodium alginate, trollooi, tragacanth gum, gum arabic, locust bean gum, guar gum, pectin, carrageenan, glue, gelatin, casein, soy protein, albumin, fully or partially saponified polyvinyl alcohol and its anions, cation modified products , Polyvinyl alcohol or polyacrylic having a degree of acetalization or butyralization of 30% or less Amide and its copolymer, polyvinylpyrrolidone and its copolymer, poly-N-vinylacetamide and its copolymer, polyethylene oxide, ethylene oxide-propylene oxide copolymer, polybutylene oxide, carboxylated polyethylene oxide, polyacryl Examples thereof include an acid and its sodium salt, a styrene-maleic anhydride copolymer, and an ethylene-maleic anhydride copolymer, but are not particularly limited to these compounds. These water-soluble resins or water-dispersible resins may be used alone or in combination of two or more.

It is optional to add a cationic substance, particles or a cross-linking agent to the ink receiving layer. However, the addition of such a substance improves ink absorbency, adsorptivity, color development, etc., and is therefore preferable. is there. As the cationic substance,
Although not particularly limited, those having a quaternary ammonium salt in the composition and using chloride, sulfate, nitrate and the like as a counter ion are preferable, and a cationic surfactant and a polymer having a cationic group may be applied. Can be. The particles are not particularly limited, but silica, colloidal silica, alumina, alumina sol, zeolite, titanium oxide, kaolin, kaolinite, talc, mica, calcium carbonate and the like can be used. Examples of the crosslinking agent include, but are not particularly limited to, methylolated or alkylolated urea-based, melamine-based,
Acrylamide-based, polyamide-based resins, epoxy compounds, isocyanate compounds, oxazoline-based compounds, aziridine compounds, various silane coupling agents, various titanate-based coupling agents, and the like can be used. Further, in the ink receiving layer, various additives, for example, antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, lubricants, pigments, dyes, organic or inorganic fine particles, fillers,
An antistatic agent and a nucleating agent may be blended.
Further, the thickness of the ink receiving layer is not particularly limited,
It is 5 to 100 μm, preferably 10 to 50 μm. If the ink receiving layer is too thin, the ink absorbency, image resolution, etc. may be poor. On the other hand, if the ink receiving layer is too thick, the drying rate may be low and the production efficiency may be poor.

The above-mentioned ink receiving layer is formed by a method of applying a coating liquid for forming an ink receiving layer on a laminated polyester film by using a coating apparatus and drying. Examples of the coating method include a blade coat method, an air knife method, a roll coat method, a brush coat method, a gravure coat method, a kiss coat method, an extrusion method, a slide hopper (slide beat) method, a curtain coat method, and a spray method. Can be used.

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

For example, intrinsic viscosity 0.5 to 0.8 dl / g
After vacuum drying PET pellets, it is supplied to an extruder,
Melted at 260 to 300 ° C, extruded into a sheet from a T-shaped die, and applied with a surface temperature of 10 to 10 using an electrostatic application casting method.
It is wound around a mirror casting drum at 60 ° C. and solidified by cooling to prepare 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.
At least one surface of this film is subjected to a corona discharge treatment, and the treated surface is coated with the coating liquid for forming a coating layer of the present invention.
The film coated with the coating liquid for forming a coating layer 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 250 times. The heat treatment is conducted for 1 to 30 seconds by leading to a heat treatment zone of ° C. to complete the crystal orientation. During this heat treatment step, if necessary,
A 12% 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 coating liquid for forming the coating layer used in this case is preferably an aqueous coating liquid in view of environmental pollution and explosion-proof properties.

The laminated polyester film of the present invention is suitably used particularly for inkjet printing. Ink jet printing is not particularly limited as long as the ink jet printing method is used. Examples thereof include various information recording materials such as OHP sheets and photographic paper, and industrial fields such as large signboards, posters, and illuminations.

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

(1) Adhesiveness On the coating layer of the laminated polyester film, NS-141LX / Takamatsu Yushi Co., Ltd.
Jurimer SPO202 manufactured by Nippon Pure Chemical Co., Ltd. (75/25
(Parts by weight) of an aqueous solution of about 10 parts by weight.
It was applied to a thickness of μm and dried at 120 ° C. The film for evaluation was conditioned at 23 ° C. and 65% RH for one day, and 100 1 mm ² cross cuts were put on the ink receiving layer.
After a cellophane tape was stuck and pressed with a rubber roller (5 reciprocations under a load of 19.6 N), the tape was peeled in the 90 ° direction. The adhesion was evaluated by the number of remaining ink receiving layers (（: 75 to 100, Δ: 50 to 74, ×: 0).
~ 49). At this time, "O" was regarded as good adhesiveness.

(2) Water resistance An ink receiving layer is formed in the same manner as in the above method (1).
The film for evaluation was conditioned for 1 day at 23 ° C. and 65% RH, and then printed on the ink receiving layer using an inkjet printer (PM-750C manufactured by Seiko Epson Corporation). Five minutes after printing, water resistance was evaluated based on whether or not the ink receiving layer had fallen off when a cut was made in the printed area with a cutter and rubbed with a finger (O: no change in the ink receiving layer, x: the ink receiving layer dropped off). did). At this time, “O” was defined as good water resistance.

(3) Hydroxyl value The hydroxyl value of the vinyl resin used in the coating layer in the present invention was determined according to JIS-K0070-1992.

[0042]

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

Example 1 0.015% by weight of colloidal silica having an average particle diameter of 0.4 μm and an average particle diameter of 1.5 μm
containing 0.005% by weight of colloidal silica
After drying T under reduced pressure at 180 ° C. for 5 hours, T was supplied to an extruder and melted at 280 ° C., and these polymers were filtered with high precision, and extruded into a sheet shape from a T-shaped die.

This was wound around a casting drum having a surface temperature of 25 ° C. by an electrostatic application casting method and cooled and solidified to produce an unstretched film. This unstretched film was stretched 3.3 times in the longitudinal direction at 90 ° C.

The film thus obtained was subjected to a corona discharge treatment in air for 3 seconds.
The coating liquid for forming a coating layer having the composition shown in Table 1 and having the following A1 / B1 was kept. The coated uniaxially stretched film is heated to 75 ° C. while being gripped with clips, stretched 3.5 times in the width direction in a state where the water content in the coating liquid on the film is 50% by weight or less, and 10 seconds at 220 ° C. Heat treatment,
A laminated polyester film having a base PET film thickness of 100 μm and a coating layer thickness of 0.15 μm was obtained.

The evaluation results of the obtained laminated polyester film are shown in Table 1.

(Comparative Examples 1 to 3, 5 and 6) Lamination was performed in the same manner as in Example 1 except that the coating liquid for forming each coating layer having the following composition was changed as shown in Table 1. A polyester film was obtained. Table 1 shows the evaluation results.

(Example 2, Comparative Example 4) A biaxially stretched polyester film ("Lumirror" E20, manufactured by Toray Industries, Inc., thickness: 50 μm) was subjected to a corona discharge treatment in air, and a table consisting of the following A1 / B1 was obtained. The coating liquid for forming a coating layer having the composition shown in No. 1 was applied using a reverse coater to obtain a laminated polyester film having a coating layer thickness of 0.2 μm. Table 1 shows the evaluation results.

Comparative Example 7 A polyester film was prepared in the same manner as in Example 1 except that the coating layer of Example 1 was not formed.

In each of the above Examples and Comparative Examples,
The resins used for forming the coating layer are as follows.

A1: Aqueous polyester resin (terephthalic acid (25 mol%), isophthalic acid (15 mol%), trimellitic acid (10 mol%), ethylene glycol (20 mol%) as a glycol component, neopentyl B1: Vinyl-based resin (2-hydroxyethyl acrylate (20 mol%), methyl methacrylate (45 mol%), methyl acrylate (Methyl acrylate (20 mol%), diethylene glycol (10 mol%)) 28 mol%), a copolymer composed of butyl acrylate (5 mol%) and acrylic acid (2 mol%), hydroxyl value: 50 mgKOH / g B2: vinyl resin (4-hydroxybutyl acrylate (30 mol%) , Methyl methacrylate (40 mol%), methyl acrylate (28 mol%), Copolymers of acrylic acid (2 mol%), hydroxyl value: 100 mg
(KOH / g) B3: Hydroxyl-free vinyl resin (Methyl methacrylate (45 mol%), butyl acrylate (30 mol%), acrylic acid (10 mol%), styrene (15 mol%) Copolymer)

[0052]

[Table 1]

[0053]

According to the present invention, an excellent laminated polyester film which can satisfy the adhesiveness to the ink receiving layer and the water resistance in ink jet printing can be obtained.

Continued on front page F-term (reference) 2C056 EA13 FC06 2H086 BA01 BA19 4F100 AA20 AK24B AK24C AK41A AK41B AK41C AL05B AL05C AR00D BA02 BA03 BA04 BA07 BA10A BA10B BA10C BA10D CC00B CC00C DE01 EJ37B00 J05 EJ37B00 J05 EJ37B00

Claims (3)

[Claims] 1. A coating film comprising a mixture of an aqueous polyester resin and a hydroxyl group-containing vinyl resin at a solid content ratio of 50/50 to 85/15 on at least one surface of a polyester film. A laminated polyester film, wherein the vinyl resin has a hydroxyl value of 30 to 80 mgKOH / g. 2. The laminated polyester film according to claim 1, wherein an ink receiving layer is further formed on the coating layer. 3. The laminated polyester film according to claim 1, which is used for inkjet printing.