JPH1148432A - Laminated polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film having an easily adhesive resin layer, prominent in adhesive property to a function layer, represented by an ink jet printing ink picture receiving layer and consisting of the principal constituents of water-soluble and hydrophilic resin such as polyvinyl alcohol and the like, a function layer and the like, represented by a photo-sensitive agent film and having the principal constituents of water soluble hydrophilic resin such as gelatin and the like. SOLUTION: A laminated polyester film is constituted of at least monoaxially oriented easily adhesive resin layer, provided on at least one side of the supporting body of biaxially oriented polyester film. In this case, the easily adhesive resin layer is provided by a method wherein coating solution, containing aromatic copolymer polyester (A) having moisture dispersing functional group and polyglycerol polyglycidyl ether (B), is applied on the polyester film and is dried.

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 biaxially oriented polyester film having at least one surface on which an easily adhesive resin layer is formed. The present invention relates to a laminated polyester formed using an adhesive resin layer. According to the present invention, it is possible to obtain a laminated polyester film excellent in adhesiveness to a functional layer containing a water-soluble / hydrophilic resin such as polyvinyl alcohol / gelatin as a main component.

[0002]

2. Description of the Related Art Polyethylene terephthalate (PET)
Alternatively, a polyester film represented by polyethylene naphthalate (PEN) has excellent properties such as mechanical strength, dimensional stability, flatness, heat resistance, chemical resistance, and optical properties, and is excellent in cost performance. It is used as a support film in various applications.

[0003] The biaxially stretched polyester film has a drawback in that the surface is highly crystallized and thus has a strong cohesive force, and therefore has poor adhesion to a functional layer for each application. In order to solve such disadvantages, a method of laminating a polyester layer having low crystallinity on the surface of a polyester film by coextrusion, a method of applying a water-dispersible polyester resin or an acrylic resin as a primer, and the like have been proposed ( JP-B-49-10243, JP-A-52-1
9786, JP-A-52-19787, JP-A-54-43017, etc.).

However, in the above-mentioned known method, a support film using a polyester resin or an acrylic resin as a primer is made of polyvinyl alcohol (PVOH).
There is a drawback that the adhesiveness to a functional layer mainly containing a water-soluble / hydrophilic resin such as gelatin is poor.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to solve the problem of water-soluble and hydrophilic resins such as polyvinyl alcohol represented by an ink jet printing ink receiving layer. To provide a laminated film having an easy-adhesion resin layer having excellent adhesion to a functional layer as a component, a functional layer mainly containing a water-soluble / hydrophilic resin such as gelatin represented by a photographic film, etc. is there.

[0006]

Means for Solving the Problems The present inventor has conducted intensive studies in view of the above problems, and as a result, has found that the above problems can be easily solved by selecting a specific easy-adhesion layer.
The present invention has been completed. That is, the gist of the present invention is a laminated polyester film in which at least one surface of a biaxially stretched polyester film support is provided with an easily adhesive resin layer stretched in at least a uniaxial direction, wherein the easily adhesive resin layer is And a coating liquid containing an aromatic copolymerized polyester (A) having a water-dispersible functional group and polyglycerol polyglycidyl ether (B), which is provided by drying. .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the present invention, as the polyester constituting the biaxially stretched polyester film, typically, for example, polyethylene terephthalate (PET) in which at least 80 mol% of the structural unit is ethylene terephthalate, and the structural unit 8
Polyethylene-2,6-naphthalate (PEN) in which 0 mol% or more is ethylene-2,6-naphthalate, poly-1,4-cyclohexane in which 80 mol% or more of the structural units is 1,4-cyclohexane dimethylene terephthalate Dimethylene terephthalate (PCT) and the like. In addition, polyethylene isophthalate, poly-
Examples include 1,4-butylene terephthalate (PBT).

[0008] Copolymerization components other than the above-mentioned superior constituents include, for example, propylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, neopentyl glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol. Diol components such as diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol, polyalkylene glycol, isophthalic acid,
Uses ester-forming derivatives such as 2,7-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, diphenyl ether dicarboxylic acid and oxymonocarboxylic acid. be able to. In addition, as a polyester, in addition to a homopolymer or a copolymer,
Small proportion blends with other resins can also be used.

In the present invention, the biaxially stretched polyester film is used as a projection-forming agent in order to impart slipperiness.
It may contain added particles, precipitated particles, and other catalyst residues. The type, size, and blending amount of these projection-forming agents are appropriately selected according to the desired slipperiness, transparency, and the like. In addition, the biaxially stretched polyester film, if necessary, an antistatic agent, a stabilizer, a lubricant, a crosslinking agent, an antiblocking agent, an antioxidant, an ultraviolet absorber, a light blocking agent,
It may contain a coloring agent and the like. Further, for whitening the film, a white pigment represented by titanium oxide, barium sulfate, magnesium oxide or the like, or a resin incompatible with polyester for the purpose of lowering the density, for example, polypropylene, polystyrene, poly-4 A void-forming agent such as methylpentene; Further, the polyester film may have a multilayer structure, in which case,
Some of the layers may be formed of a polymer other than polyester.

[0010] The laminated polyester film of the present invention comprises a biaxially stretched polyester film having at least one surface provided with an easily adhesive resin layer. The greatest feature of the present invention is that a coating solution in which an easily adhesive resin layer for forming the above-mentioned laminated film contains an aromatic polyester (A) having a water-dispersible functional group and polyglycerol polyglycidyl ether (B). Is applied and dried, and the easy-adhesion layer is stretched in at least one axial direction.

An aromatic copolymerized polyester having a water-dispersible functional group, polyglycerol polyglycidyl ether,
The easy-adhesion layer containing a reaction product of these heats enhances the adhesion between the biaxially stretched polyester film support and the hydrophilic functional layer. Hereinafter, for convenience, the aromatic copolymer polyester (A) having a water-dispersible functional group contained in the easily adhesive resin layer is referred to as an easily adhesive polyester.

The easily adhesive polyester (A) of the present invention can be synthesized by a usual polycondensation reaction using the following hydroxy compound and carboxylic acid compound as raw materials. As the hydroxy compound to be copolymerized with the easily adhesive polyester of the present invention, an aliphatic hydroxy compound compound,
An alicyclic hydroxy compound and an aromatic hydroxy compound, preferably an aliphatic hydroxy compound and an alicyclic hydroxy compound are copolymerized.

When a condensed diol of ethylene glycol such as diethylene glycol is used, its component is not more than 20 mol%, more preferably not more than 10 mol%, especially not more than 5 mol%, based on all hydroxy compound components contained in the easily adhesive polyester. When the amount of the component is too large, it may be difficult to exhibit sufficient blocking resistance and adhesiveness as an easily adhesive resin layer.

When an aromatic hydroxy compound is used, the content of the hydroxy compound component is preferably at most 5 mol%, more preferably at most 2 mol%, based on all the hydroxy compound components contained in the easily adhesive polyester. If the amount of the component is too large, sufficient adhesiveness may not be obtained as the easily-adhesive resin layer. Furthermore, sufficient stretching aptitude may not be obtained in the process of stretching the easily adhesive resin layer together with the base polyester film.

As the carboxylic acid compound copolymerized with the easily adhesive polyester of the present invention, an aromatic carboxylic acid compound,
There are alicyclic carboxylic compounds and aliphatic carboxylic compounds. When an aromatic carboxylic acid compound is used, the carboxylic acid component is 100 mol% or less, preferably 95 mol% or less, particularly 90 mol% or less, based on all carboxylic acid components contained in the easily adhesive polyester. preferable.
The smaller the amount of the component, the more easily the adhesive resin layer can exhibit sufficient adhesiveness. The lower limit of the total carboxylic acid component contained in the easily adhesive polyester of the aromatic carboxylic acid compound is 5
0 mol% or more. When the component is 50 mol% or less,
In some cases, it becomes difficult to exhibit sufficient blocking resistance as an easily adhesive resin layer.

When an aliphatic carboxylic acid compound is used, its carboxylic acid component accounts for not more than 20 mol%, more preferably not more than 10 mol%, especially not more than 5 mol%, based on all carboxylic acid components contained in the easily adhesive polyester. It is preferable that when the amount of the component increases, the adhesiveness of the easily adhesive resin layer is excellent, but it may be difficult to exhibit sufficient blocking resistance.

The carboxylic acid component in the composition of the easily adhesive polyester is obtained by copolymerizing an aromatic carboxylic acid compound in an amount of 50 mol% or more and an alicyclic carboxylic acid in an amount of 50 mol% or less based on all carboxylic acid components. preferable. The ester-forming compound having a water-dispersible functional group constituting the easily adhesive polyester of the present invention is, for example, an ester containing an organic acid group such as a hydroxyl group, a sulfonic acid group, a carboxylic acid group, a phosphoric acid group and / or a base thereof. It is a forming compound, preferably an aromatic carboxylic acid compound having a sulfonic acid salt, an aromatic carboxylic acid compound having a carboxylic acid salt, a hydroxy compound having a sulfonic acid salt, or a hydroxy compound having a carboxylic acid salt is used. . Among these, an aromatic carboxylic acid compound having a sulfonic acid salt and a hydroxy compound having a carboxylic acid salt are particularly preferably used.

The ester-forming compound having a water-dispersible functional group is used in an amount of 1 to 1 with respect to all hydroxy compounds or all carboxylic acid compounds forming an easily adhesive polyester.
It is preferably in a range of 5 mol%, more preferably 1 to 12 mol%, particularly preferably 3 to 12 mol%. If the amount of the component is too large, it may be difficult to obtain sufficient adhesiveness and blocking resistance as an easily adhesive layer. If the amount of the component is too small, the adhesiveness and applicability tend to decrease when a hydrophilic resin layer such as polyvinyl alcohol is provided as the functional layer.

The easily-adhesive polyester used in the present invention is desirably a copolymer polyester comprising the structural units in the above-mentioned range. The average molecular weight (by GPC) of the easily adhesive polyester is not particularly limited, but is preferably 5000 or more, preferably 8000 or more. If the average molecular weight of the easily-adhesive polyester is less than 5,000, the adhesion of the easily-adhesive resin layer to the water-resistant / functional layer tends to decrease. The lower limit of the glass transition temperature (Tg) of the easily adhesive polyester is preferably 20 ° C. or more, more preferably 30 ° C. or more, and particularly preferably 40 ° C. or more. If the glass transition temperature is less than 20 ° C., sufficient anti-blocking properties may not be obtained when an easily adhesive resin layer is formed. Further, the upper limit of the glass transition temperature of the easily adhesive polyester is preferably 140 ° C. or less. If the glass transition temperature exceeds 140 ° C., it may be difficult to obtain sufficient stretchability in the process of stretching the easily adhesive resin layer together with the base polyester film.

The polyglycerol polyglycidyl ether (B) used in the present invention is a compound synthesized mainly from glycerin and epichlorohydrin. The average molecular weight of the compound is not particularly limited, but is 1200 or less, preferably 250 or less. １０００1000 are used. As the average molecular weight increases, the degree of water solubility decreases, and it tends to be difficult to use the composition for aqueous coating. The glycidyl compound contains at least two, preferably three or more glycidyl groups in the molecule. Further, the glycidyl compound contains at least one, preferably two or more hydroxyl groups in the molecule. These functional groups may undergo a condensation reaction between glycidyl groups and hydroxyl groups in molecules between molecules or within molecules by heat in the easily adhesive resin layer.

In the present invention, the above-mentioned easy-adhesion polyester (A) and polyglycerol polyglycidyl ether (B) react by the heat of the step of forming the easy-adhesion resin layer,
The product is present in the easily adhesive resin layer. The reaction format is
Including any reaction, for example, the following examples are given. That is, glycidyl of polyglycerol polyglycidyl ether (B) is combined with hydroxyl group, carboxylic acid group, or hydroxyl group, carboxylic acid group, carboxylic acid group, etc. introduced for improving water dispersibility as terminals in easily adhesive polyester (A). It refers to a condensation reaction product between different molecules caused by heat with a group, a condensation reaction product between the same kind of molecules of a glycidyl group and a hydroxyl group of polyglycerol polyglycidyl ether (B), a hybrid product thereof and the like.

The water-soluble resin (C) used in the present invention is represented by polyvinyl alcohol, polyvinylpyrrolidone, gelatin and modified products thereof. The polyvinyl alcohol that can be used in the present invention can be synthesized by a usual polymerization reaction. The polyvinyl alcohol used in the present invention is not particularly limited as long as it is water-soluble. The degree of polymerization of the polyvinyl alcohol of the present invention is not particularly limited, but usually 100 or more, preferably 300 to 40,000 is used. If the degree of polymerization is less than 100, the water resistance of the easily adhesive resin layer tends to decrease. The saponification degree of the polyvinyl alcohol of the present invention is not particularly limited, but is 70 mol% or more,
A saponified polyvinyl acetate having a content of preferably 70 to 99.9 mol% is practically used.

The polyvinylpyrrolidone which can be used in the present invention can be synthesized by a usual polymerization reaction. Although the polyvinylpyrrolidone of the present invention may be a homopolymer, the content of the vinylpyrrolidone component is 50%.
A copolymer with another monomer component having an addition-polymerizable unsaturated group represented by another vinyl group, allyl group or acryl group may be used as long as the amount does not fall below the weight%.

Other monomers having an addition-polymerizable unsaturated group copolymerized with polyvinylpyrrolidone include an alkyl group, an alkyl ester group, an alkyl ether group, an alkylol group, an amide group, a hydroxyl group and an amino group in the side chain. (Secondary / tertiary / quaternary), polyalkyl ether, carboxylic acid group, carboxylic acid group, carboxylic acid ester group,
Those having a sulfonic acid group, a sulfonic acid group, a sulfonic acid ester group, a phosphoric acid group, a phosphate group, and a phosphoric acid ester group are selected.

The polyvinylpyrrolidone which can be used in the present invention generally has a weight average molecular weight of 40,000 or more, preferably in the range of 50,000 to 3,000,000. When the average molecular weight is less than 40,000, the water resistance of the easily adhesive resin layer tends to decrease. The gelatin that can be used in the present invention can be obtained by decomposing and purifying collagen as a raw material by a conventional method. The gelatin of the present invention may be a low-molecular-weight gelatin which is no longer gelled by the enzyme treatment.

Further, in the easily adhesive resin layer of the present invention, if necessary, inert particles (D) may be contained in order to improve the slipperiness of the film surface. The inert particles (D) include inorganic inert particles and organic inert particles. As the inorganic inert particles, for example, silica sol, alumina sol,
Examples include calcium carbonate and titanium oxide. Examples of the organic inert particles include fine particles containing a homopolymer or a copolymer of a polystyrene resin, a polyacrylic resin, and a polyvinyl resin, or organic particles represented by crosslinked particles obtained by combining these with a crosslinkable component. These inert particles preferably have a softening temperature or decomposition temperature of about 200 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably 300 ° C. or higher.

The average particle size (d) of the inert particles (D) is expressed by a ratio (d / l) when the average thickness of the easily adhesive resin layer is (L).
Is preferably in the range of usually 1/3 to 3, preferably 1/2 to 2. The mixing ratio of the easily-adhesive polyester (A), polyglycerol polyglycidyl ether (B), and water-soluble resin (C) contained in the coating solution used to form the easily-adhesive resin layer of the film of the present invention is represented by the following formula: Is preferably in a range that simultaneously satisfies

[0028]

1/9 ≦ (A) / {(B) + (C)} ≦ 9/1 2/8 ≦ (B) / (C) If the content of the easily-adhesive polyester (A) is too small, In some cases, sufficient adhesiveness with the base polyester film cannot be obtained. In order to obtain sufficient adhesiveness as an easily adhesive layer, the content is preferably 20 parts by weight or more.

If the amounts of the polyglycerol polyglycidyl ether (B) and the water-soluble resin (C) are too small, sufficient adhesiveness with a functional layer made of a hydrophilic resin may not be obtained. In order to obtain sufficient adhesiveness as an easily-adhesive resin layer, it is preferable to contain 10 parts by weight or more. If necessary, a water-soluble or water-dispersible binder resin other than the above-mentioned easily adhesive polyester may be used in the easily adhesive resin layer in the present invention. Examples of such a binder resin include polyurethane, acrylic resin, vinyl resin, epoxy resin, and amide resin. Each of these skeleton structures may have a substantially composite structure by copolymerization or the like. As a binder resin having a composite structure, for example, acrylic resin-modified polyester,
Examples include acrylic resin-modified polyurethane, vinyl resin-modified polyester, and vinyl resin-modified polyurethane.

The amount of the binder component other than the easily-adhesive polyester is 50 parts by weight or less based on the weight of the coating layer.
Further, the range is preferably 30 parts by weight or less. Further, the easily adhesive resin layer of the present invention may contain a crosslinking reactive compound as required. The cross-linking reactive compound mainly undergoes a cross-linking reaction with the functional group of the resin contained in the easily-adhesive resin layer, whereby the cohesiveness of the easily-adhesive resin layer, surface hardness, abrasion resistance,
Solvent resistance and water resistance can be improved. The crosslinking reactive compound may be a low molecular weight compound or a high molecular polymer having a reactive functional group as long as the reactive functional group always contains two or more functional groups in one molecule.
The compounding amount of the crosslinking reactive compound is preferably in the range of 20 parts by weight or less, more preferably 10 parts by weight or less in parts by weight based on the easily adhesive resin layer.

The easily adhesive resin layer of the present invention may contain, if necessary, a surfactant, an antifoaming agent, a coating improver, a thickener, a low molecular antistatic agent, an organic lubricant, an antioxidant, and an ultraviolet absorber. It may contain a small amount of additives such as an agent, a foaming agent, a dye, and a pigment. These additives may be used alone or in combination of two or more as needed. The easily adhesive resin layer of the present invention may be formed on only one side of the polyester film, or may be formed on both sides. When forming on only one side,
On the opposite surface, a layer different from the easy-adhesion resin layer may be formed as necessary, so that the recording sheet support of the present invention can be provided with other characteristics. The film before application may be subjected to a chemical treatment, a discharge treatment, or the like, in order to improve the coating property and adhesion of the coating solution to the film. Further, in order to further improve the surface characteristics of the recording sheet support of the present invention, a discharge treatment may be performed after forming the easily adhesive resin layer.

The thickness of the easily adhesive resin layer is 0.01 to 2 μm.
m, more preferably 0.02 to 0.5 μm, especially 0.03 to
A range of 0.2 μm is preferred. When the thickness of the easily-adhesive resin layer is less than 0.01 μm, sufficient adhesiveness may not be obtained, and when it exceeds 2 μm, the blocking resistance tends to be insufficient. As a method for producing the biaxially stretched polyester film, a known method can be employed. For example, a pre-dried polyester chip and necessary additives are mixed, put into a hopper into an extruder, melt-kneaded at a temperature of 200 to 300 ° C. in an extruder, extruded from a die into a sheet, and heated to about 70 ° C. or less. The sheet is quenched on a casting drum (rotary cooling drum) to obtain an unstretched sheet, and the obtained sheet is stretched in the longitudinal and / or transverse directions at an area magnification of at least 4 times, preferably at least 9 times, and
A method of performing heat setting at a temperature of 20 to 200 ° C. can be adopted.

The method of forming the easily adhesive resin layer on the surface of the biaxially stretched polyester film is not particularly limited, but a method of applying a coating solution of the easily adhesive resin during the process of producing the polyester film is preferably employed. . In particular,
A method of applying and drying a coating liquid for forming an easily adhesive resin layer on the surface of an unstretched sheet, a method of applying and drying a coating liquid for forming an easily adhesive resin layer on the surface of a uniaxially stretched film, and a method of drying the surface of a biaxially stretched film. A method of applying a coating liquid for forming an easily-adhesive resin layer and drying the applied liquid can be used. Among these methods, it is economical to apply a coating solution for forming an easily-adhesive resin layer on the surface of an unstretched film or a uniaxially stretched film, and then simultaneously dry-harden the coating layer in the process of performing heat treatment on the film of the laminated film. is there.

Further, as a method for forming the easily-adhesive resin layer, a method in which some of the above-mentioned coating methods are used in combination may be employed, if necessary. Specifically, there is a method in which the first layer is applied to the surface of the unstretched sheet and dried, then stretched in a uniaxial direction, and then the second layer is applied and dried. In the film obtained by this method, the object of the present invention is achieved if the layer forming the outermost layer of the film is a laminated film which is the easily adhesive resin layer of the present invention.

As a method of applying a coating solution of an easily adhesive resin to the surface of a polyester film, a reverse roll coater, a gravure coater, a rod coater, an air coater, which is described in “Coating System”, written by Yuji Harasaki, Maki Shoten, 1979. A doctor coater or the like can be used. It is preferable that the coating liquid used in the formation of the easily-adhesive resin layer of the present invention is usually adjusted with water as a main medium from the viewpoint of safety and hygiene. As long as water is the main medium, a small amount of an organic solvent may be contained for the purpose of improving dispersion in water or improving film forming performance. When the organic solvent is used by mixing with water as a main medium, it is necessary to use the organic solvent within a range that dissolves in water. The organic solvent may be used alone, but may be used in combination of two or more as needed.

[0036]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist. In addition, the measuring method and definition of various physical properties and characteristics in the present invention are as follows. (1) Aqueous resin adhesiveness 1 Aqueous resin: Polyvinyl acetal (Sekisui Chemical Co., Ltd., SLEX KX-1, hereinafter referred to as KX1) is applied to the surface of the easily adhesive layer and dried. The application is KX1 adjusted to 8% by weight.
Is applied using a baker-type applicator so that the solution coating thickness immediately after the coating is about 127 μm. After coating, the coating layer is immediately heated in an oven at 100 ° C. for 4 minutes to dry the coating layer. The surface of the dried KX1 coating layer is printed in black (12 cm × 12 cm area) with an inkjet printer (BJC-600J manufactured by Canon) and air-dried for about 12 hours (23 ° C., 50% RH). A cellophane tape (Nichiban, 18 mm width) was adhered to the printing surface, and the state of peeling at the time of rapid peeling was visually observed and judged according to the following criteria.

[0037]

[Table 1] 未 満 Less than 10% peeling: ○ (good) 10% or more, less than 50% peeling: △ (normal) 50% or more Peeling: × (poor) ───────────────────── (2) Aqueous resin adhesiveness 2 Aqueous resin: Polyvinyl acetal (Sekisui Chemical S-Lek KX-1, below) KX1) is applied to the surface of the easily adhesive layer and dried. The application is KX1 adjusted to 8% by weight.
Is applied using a baker-type applicator so that the solution coating thickness immediately after the coating is about 127 μm. After coating, the coating layer is immediately heated in an oven at 100 ° C. for 4 minutes to dry the coating layer. The surface of the dried KX1 coating layer is printed in black (12 cm × 12 cm area) with an inkjet printer (BJC-600J manufactured by Canon) and air-dried for about 12 hours (23 ° C., 50% RH). A cross cut of 100 squares was made on the print surface at intervals of 1 mm, and a cellotape (18 mm width, made by Nichiban) was adhered thereon, and the state of peeling when the film was rapidly peeled was visually observed and judged according to the following criteria.

[0038]

[Table 2] 未 満 Less than 10% peeling: ○ (good) 10% or more, less than 50% peeling: △ (normal) 50% or more Peeling: × (poor) ───────────────────── (3) Anti-blocking property The easy-adhesive resin layer surface of the support film was superposed, and the temperature was 40 ° C.
Pressing is performed at 80% RH under a load of 10 kg / cm ² for 20 hours, and the pressed film surface is peeled off according to the method of measuring and quantifying the degree of blocking between plastic films determined by ASTM D1893. The degree of blocking was determined from the load applied to. The criteria are as follows.

[0039]

[Table 3] 以上 50 g or more and less than 100 g: ○ (good) 100 g or more and less than 250 g: △ (normal) 250 g or more: × (poor) ─バ イ ン ダ ー In Examples and Comparative Examples, binder resins and the like used for forming the easily adhesive resin layer are as follows. (Examples of compounds) Binder resin: A1 Terephthalic acid (45 mol%) as a dicarboxylic acid component, 5-sodium sulfoisophthalic acid (5 mol%)
Copolymerized polyester binder resin containing ethylene glycol (40 mol%) and diethylene glycol (10 mol) as diol components: A2 Terephthalic acid (10 mol%) and isophthalic acid (40 mol%) as dicarboxylic acid components ), And ethylene glycol (8 mol%), diethylene glycol (32 mol%), neopentyl glycol (6 mol%), dimethanol propionate (4 mol)
Copolymerized polyester binder resin containing: A3 dicarboxylic acid components as terephthalic acid (20 mol%), isophthalic acid (15 mol%), cyclohexanedicarboxylic acid (10 mol%), 5-sodium sulfoisophthalic acid (5 mol%) ), And as a diol component,
Ethylene glycol (31 mol%), diethylene glycol (4 mol%), cyclohexanedimethanol (15 mol%)
Mol%) Polyglycerol polyglycidyl ether: B1 Denacol EX-521 (manufactured by Nagase Kasei), average molecular weight = 1000 Water-soluble resin 1: C1 polyvinyl alcohol having a saponification degree of 88 mol% and a polymerization degree of 1700 Inert particles: D1 Silica sol having an average particle diameter of 0.05 μm Example 1 After transesterification according to a conventional method, silica particles having an average particle diameter of 1.4 μm dispersed in ethylene glycol were added. Next, a polycondensation reaction was carried out according to a conventional method to obtain polyethylene terephthalate having an intrinsic viscosity of 0.65.
This polyethylene terephthalate was melt-extruded at a temperature of 280 to 300 ° C. and cast on a cooling drum while using an electrostatic adhesion method to obtain an amorphous film having a thickness of about 720 μm. This film was stretched 3.7 times in the machine direction at 85 ° C., and further 3.9 times in the transverse direction at 100 ° C.
Heat treatment was performed at 10 ° C. to obtain a biaxially stretched polyester film having a thickness of 50 μm.

After longitudinal stretching of the polyester film obtained by the above formulation, 55 parts by weight of the easily adhesive polyester (A1) shown in the above compound example, polyglycerol polyglycidyl ether (denacol)
EX-521: An aqueous dispersion containing 10 parts by weight of B), a water-soluble resin (C) and 5 parts by weight of inert particles (silica sol: D) was prepared, and the film thickness after stretching and drying was 0.05 μm. To obtain a laminated film.

Examples 2-5 and Comparative Examples 1-5 A laminated film was obtained in the same manner as in Example 1, except that the composition of the easily adhesive resin layer was changed as shown in Table 1 below. .

[0042]

[Table 4] Table 1 組 Composition of coating liquid (parts by weight) L (A) (B) (C) (D) (μm) d / L ──────────────────────────────── ─ Example 1 A1 = 55 B1 = 10 C1 = 30 D1 = 5 0.05 1 Example 2 A1 = 35 B1 = 30 C1 = 30 D1 = 5 0.05 1 Example 3 A1 = 35 B1 = 30 C1 = 30 D1 = 5 0.03 0.6 Example 4 A1 = 65 B1 = 30 D1 = 5 0.05 1 Example 5 A2 = 65 B1 = 30 D1 = 5 0.05 1 Example 6 A3 = 55 B1 = 40 D1 = 5 0.05 1 Comparative example 1 A1 = 95 D1 = 5 0.05 1 Comparative example 2 A2 = 95 D1 = 5 0.05 1 Comparative example 3 A3 = 95 D1 = 5 0.05 1 Comparative example 4 B1 = 95 D1 = 5 0.05 1 Comparative example 5 C1 = 95 D1 = 5 0.05 1 ─ ──────────────────────────────── The evaluation results of the obtained easily adhesive film are summarized in Table 2 below. Show.

[0043]

[Table 5]

[0044]

According to the present invention, a functional layer such as polyvinyl alcohol is used for an OHP film, a label, a plotter film, a photographic film, a photographic printing paper film, a bar code label, a magnetic card, a graphic arts and the like. In all applications where a layer containing an aqueous resin is used, a film having good adhesiveness can be provided, and its industrial value is high.

Claims (4)

[Claims] 1. A laminated polyester film comprising at least one surface of a biaxially stretched polyester film support provided with an easily adhesive resin layer stretched in at least one direction, wherein the easily adhesive resin layer is dispersed in water. A laminated polyester film provided by applying and drying a coating solution containing an aromatic copolymerized polyester (A) having a polyfunctional functional group and polyglycerol polyglycidyl ether (B). 2. The laminated polyester film according to claim 1, wherein the coating liquid contains a water-soluble resin (C). 3. The easy-adhesion resin layer contains inert particles (D), and the thickness (L) of the easy-adhesion resin layer and the average particle size (d) of the inactive particles satisfy the following expression. The laminated polyester film according to claim 1 or 2, wherein [Formula 1] 1/3 ≦ d / L ≦ 3 4. Resins (A) and (B) contained in a coating solution
The laminated polyester film according to any one of claims 1 to 3, wherein the weight ratio of (C) and (C) simultaneously satisfies the following expression. 1/9 ≦ (A) / {(B) + (C)} ≦ 9/1 2/8 ≦ (B) / (C)