JP2002079747A - Polyester film easily bondable with ink image accepting layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester film easily bondable with an ink image accepting layer, which is excellent in opacifying properties, water resistant adhesion to the water-based ink image accepting layer of an ink jet printer or the like, a conveyability, antistatic properties and useful for an image accepting paper. SOLUTION: On one side of a polyester film, on the other side of which an antistatic coating film is provided, a coating film easily bondable with the ink image accepting layer is provided for forming a laminating film or the polyester film easily bondable with the ink image accepting layer. The coating film easily bondable with the ink image accepting layer is mainly made of a composition consisting of 30 to 80 wt.% of a copolyester (A) having a secondary transition point of 20 to 90 deg.C, 15 to 45 wt.% of a polyvinyl alcohol (B) having a saponification degree of 80 to 90 mol%, 3 to 25 wt.% of particles (C) having an average particle diameter of 20 to 80 nm and 5 to 20 wt.% of a compound (D) represented by formula (I) under the condition that the surface energy of 50 to 90 mN/m. In the formula (I), R represents formulae (II), (III) and (IV).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester film having a good adhesion to an ink image-receiving layer, and more particularly to an excellent concealing property, excellent water-resistant adhesion to an aqueous ink image-receiving layer of an ink jet printer or the like, and excellent transportability and antistatic property. The present invention relates to an excellent ink-receiving layer adhesive polyester film useful for an image-receiving paper.

[0002]

2. Description of the Related Art A polyester film represented by a polyethylene terephthalate film has been widely used as a base film of a film for an image receiving paper.
In recent years, with the demand for color printers, new printing methods such as an ink jet method have been developed. Such a film for an image receiving paper for a printing system is disclosed in JP-A-64-364.
No. 79 and Japanese Patent Application Laid-Open No. 1-95091, it is necessary to form an ink image receiving layer on a film. The ink image receiving layer is porous and has good ink absorbency, but the ink image receiving layer has poor adhesion to a polyester film used as a base film.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink receiving layer which is excellent in adhesiveness and concealing property with an ink receiving layer, and has both transportability and antistatic property and is useful for an image receiving paper for an ink jet printer. It is an object of the present invention to provide a layer-adhesive polyester film.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
According to the present invention, a polyester film is provided with an ink-receiving layer easy-adhesion coating film on one surface and a laminated film provided with an antistatic coating film on the other surface. Copolyester (A) having a transition point of 20 to 90 ° C, 30 to 80% by weight, saponification degree 80 to 90 mol%
15 to 45% by weight of polyvinyl alcohol (B), 3 to 25% by weight of fine particles (C) having an average particle diameter of 20 to 80 nm, and 5 to 20% by weight of a compound (D) represented by the following formula (I).
And a surface energy of the ink image-receiving layer easy-adhesion coating film is 50 to 70 mN / m.

[0005]

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[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

[Polyester Film] In the present invention, the polyester constituting the polyester film is a polyester comprising a dicarboxylic acid component and a glycol component, such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-polyester. Polyester composed of an aromatic dicarboxylic acid component such as diphenyldicarboxylic acid and a glycol component such as ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and 1,6-hexanediol is preferable. Especially polyethylene terephthalate, polyethylene
2,6-Naphthalenedicarboxylate is preferred. Further, a copolymerized polyester such as the above components may be used.

If necessary, organic or inorganic fine particles as a lubricant may be added to the polyester to improve the winding property in producing the film and the transport property of the film in coating the ink image receiving layer. It is preferable to include them. Examples of such fine particles include calcium carbonate, calcium oxide, aluminum oxide, kaolin, silicon oxide, zinc oxide, crosslinked acrylic resin particles, crosslinked polystyrene resin particles, urea resin particles, melamine resin particles, crosslinked silicone resin particles, and the like. Also, besides fine particles, colorants, antistatic agents, antioxidants, lubricants, catalysts, polyethylene, polypropylene, ethylene-propylene-polymer, other resins such as olefinic ionomers, etc., as long as the transparency is not impaired. It can be arbitrarily contained.

In the polyester film of the present invention, as an antistatic coating film, 5 to 50% by weight of an antistatic agent (E) comprising a polycationic polymer, a polyester resin (F-1) and an acrylic resin (F -2) at least one binder resin (F) selected from the group consisting of:
It is preferable to provide a coating film containing 40 to 85% by weight, and use a white polyester film (white polyester film) having a gloss of 60 ° or more and a light transmittance of 20% or less and white. This white polyester film
The polyester can be obtained by adding a white pigment, for example, titanium oxide and / or barium sulfate, for example, in an amount of 5 to 20% by weight. In addition, the white polyester film preferably has a gloss of 50 or more from the sharpness of the printed matter when used as an image receiving paper, and preferably has a light transmittance of 20% or less from the design of the printed matter.

[0010] The polyester film in the present invention comprises:
A biaxially stretched film having a heat shrinkage of 1% or less when held at 150 ° C. for 30 minutes has good dimensional stability when a polyester film is used as an image receiving paper, and suppresses printing misalignment and the like. It is preferable because it is possible. A biaxially stretched film having such a heat shrinkage is obtained by, for example, setting the density of the film to 1.390 g / cm ³ or more by heat setting or heat treatment at a temperature equal to or higher than Tg of the polyester after biaxial stretching. be able to.

In the present invention, a copolyester (A), a polyvinyl alcohol (B), a fine particle (C) and a compound represented by the following formula (I) are used as the ink-receiving layer easily adhesive coating on a polyester film. Is laminated with a compound (D) as a main component.

[0012]

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The copolyester (A) used as the component for forming the ink image-receiving layer coating film is a copolymerized polyester comprising a polycarboxylic acid component and a hydroxy compound component, and is terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid. Acid, hexahydroterephthalic acid, 4,4'-
Polycarboxylic acid components such as diphenyldicarboxylic acid, phenylindanedicarboxylic acid, adipic acid, sebacic acid, 5-sulfoisophthalic acid, trimellitic acid, dimethylolpropionic acid, and 5-Na sulfoisophthalic acid;
-K sulfoisophthalic acid, a dicarboxylic acid component having a sulfonic acid group such as 5-K sulfoterephthalic acid, ethylene glycol, diethylene glycol, neopentylene glycol, 1,4-butanediol, 1,6-hexanediol, 4-cyclohexanedimethanol, glycerin, trimethylolpropane, bisphenol-A
And a hydroxy compound such as an alkylene oxide adduct of the formula (I), which is used as an aqueous solution, aqueous dispersion or emulsion.

The secondary transition point (T) of the copolyester (A)
g) is from 20 to 90C, preferably from 25 to 80C.
If the Tg is less than 20 ° C., the film is likely to be blocked, while if it exceeds 90 ° C., the abrasion and adhesion of the film are undesirably reduced.

In the copolyester (A), the dicarboxylic acid component having a sulfonic acid group for imparting hydrophilicity is present in an amount of 1 to 16 mol% based on all carboxylic acid components in the molecule.
And preferably 1.5 to 14 mol%. When the dicarboxylic acid component having a sulfonic acid group is less than 1 mol%, the hydrophilicity of the copolyester (A) is insufficient,
On the other hand, if it exceeds 16 mol%, the moisture resistance of the coating film is undesirably reduced.

The polyvinyl alcohol (B) used as a component for forming the above-mentioned ink-receiving layer easily adhesive coating film must have a saponification degree of 80 to 90 mol%. If the degree of saponification is less than 80 mol%, the moisture resistance of the coating film is reduced. On the other hand, if it exceeds 90 mol%, the adhesion to the ink receiving layer is undesirably reduced.

The fine particles (C) used as a component for forming the above-mentioned ink image-receiving layer easily adhesive coating film are organic or inorganic fine particles having a particle diameter of 20 to 80 nm. Examples of such fine particles include calcium carbonate, calcium oxide, aluminum oxide, kaolin, silicon oxide, zinc oxide, crosslinked acrylic resin particles, crosslinked polystyrene resin particles, melamine resin particles, crosslinked silicone resin particles, and the like. If the particle size of the fine particles is less than 20 nm, the film is likely to be blocked, while if it exceeds 80 nm, the shaving property is undesirably reduced.

Further, the compound (D) used as a component for forming the above-mentioned ink image-receiving layer easy-adhesion coating film is a compound represented by the above formula (I). Performance becomes insufficient.

In the present invention, the components constituting the ink-receiving layer easy-adhesion coating film, the copolyester (A), the polyvinyl alcohol (B), the fine particles (C), and the compound (D) are compounded in the copolyester ( A) 30-80% by weight,
The content is 15 to 45% by weight of polyvinyl alcohol (B), 3 to 35% by weight of fine particles (C), and 5 to 20% by weight of compound (D). If the proportion of the component (A) is less than 30% by weight, the adhesion to the polyester film is insufficient, while if it exceeds 80% by weight, the adhesion to the ink image receiving layer is undesirably reduced. If the proportion of the component (B) is less than 15% by weight, the adhesion to the ink image-receiving layer is insufficient, while if it exceeds 45% by weight, the blocking resistance of the film is undesirably reduced. On the other hand, if the proportion of the component (C) is less than 3% by weight, the lubricity (transportability) of the film is insufficient, while if it exceeds 25% by weight, the shaving property is undesirably reduced. When the proportion of the component (D) is less than 5% by weight, the adhesion to the ink image-receiving layer after printing with an ink jet printer is insufficient. On the other hand, when the proportion exceeds 20% by weight, the blocking resistance is reduced and the adhesion to the polyester film is poor. It is not preferable because it decreases.

Further, the surface energy of the ink-receiving layer easy-adhesion coating film in the present invention needs to be 50 to 70 mN / m, and particularly preferably 52 to 65 mN / m. If the surface energy is less than 50 mN / m, the coating properties and adhesiveness of the aqueous ink image-receiving layer will be poor, and if it exceeds 70 mN / m, the adhesion to the polyester film as the substrate will be insufficient, and the moisture resistance of the coating film will be insufficient. It is not preferable because the property may be insufficient.

The ink-receiving layer easily adhesive coating film having a surface energy of 50 to 70 mN / m is an ink in which the copolyester (A), polyvinyl alcohol (B), fine particles (C) and compound (D) are within the scope of the present invention. It can be obtained by laminating the image-receiving layer easily adhesive coating film, for example, with a thickness of 0.02 to 1 μm.

[Antistatic coating film] As an antistatic coating film (antistatic coating film), a coating film containing a low-molecular type or high-molecular type antistatic agent in the coating film is known. . As the low molecular weight antistatic agent, a surfactant type anionic antistatic agent such as a long chain alkyl compound having a sulfonate group (JP-A-4-28728) is known. Examples of the antistatic agent of the type include polymers having an ionized nitrogen element in the main chain thereof (JP-A-3-255139).
JP-A-4-288127, JP-A-6-320390
No.) and sulfonic acid group-modified polystyrene (Japanese Unexamined Patent Publication No.
No. 320394) is known.

However, in the case of an antistatic coating film using a low-molecular type antistatic agent, there is a problem that a part of the antistatic agent moves in the coating film, accumulates at the interface, and migrates to the opposite surface of the film. In addition, there is a problem that the antistatic property decreases with time. On the other hand, in the case of an antistatic coating film using a polymer type antistatic agent, a large amount of an antistatic agent is required to obtain good antistatic properties, and a thick antistatic coating film is required. It is not economical because it needs to be formed. In addition, when a scrap film that has not become a product (for example, a film end portion cut and removed in a manufacturing process) is collected and used as a reclaimed material for film production, it is included in the reclaimed material during melt film formation. There are problems such as the coating film components being thermally degraded and the resulting film being markedly colored and lacking practicality (recoverability is poor).

Further, disadvantages such as difficulty in peeling (blocking) between the films and easiness of shaving of the coating film occur, and it is desired to solve them. From these problems, the antistatic agent (E) used in the present invention is preferably a polycationic polymer. Examples of the polycation polymer include a compound having a repeating unit having a structure represented by the following formula (II) as a main component.

[0025]

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Wherein R ¹ and R ² are each H or CH ₃ , R ³ is an alkylene group having 2 to 10 carbon atoms, R ⁴ ,
R ⁶ is a saturated hydrocarbon group having 1 to 5 carbon atoms, R ⁶ is an alkylene group having 2 to 10 carbon atoms, p is a number of 1 to 20,
q is a number of 1 to 40; Y ^- is a halogen ion, mono- or polyhalogenated alkyl ion, nitrate ion, sulfate ion, alkyl sulfate ion, sulfonate ion or alkyl sulfonate ion.

[0027] Among the anti-static agent, wherein in formula (II) Y ^- alkyl sulfonate ion represented by (wherein, saturated hydrocarbon group of R ⁷ has a carbon number 1 to 5) ^- is R ⁷ SO ₃ Yes, - (OR ³⁾ p- of R ³ is an ethylene group, the number of p is ^{1~20, - (R 6 O)} R 6 in q- is an ethylene group, the number of q is from 1 to 40 Is preferred because the adhesiveness between the coating film and the polyester film and the heat resistance of the coating film are good, and particularly, the antistatic property is excellent.

The antistatic agent can be preferably produced, for example, by the following method. That is, the acrylate monomer is subjected to emulsion polymerization to obtain a weight average molecular weight of 2
000 to 100,000 polyacrylate and
Then, N, N-dialkylaminoalkylamine (for example, N, N-dimethylaminopropylamine, N, N-
Amidation by reaction with diethylaminopropylamine or the like) and finally a quaternary hydroxyalkylation reaction to introduce a quaternary cation pair.

Average molecular weight of antistatic agent (number average molecular weight)
Is optional, but 3000 to 300,000, and further 500
It is preferably from 0 to 100,000. When the average molecular weight is less than 3,000, the back transferability of the antistatic agent tends to deteriorate, while when the average molecular weight exceeds 300,000, the viscosity of the aqueous coating solution becomes too high, making it difficult to uniformly coat the film. Therefore, it is not preferable.

The antistatic agent used for the antistatic film is as follows:
Formula (II) Y in ^{- _{is, CH 3 SO 3 -, C}} 2 H 5 SO 3 -, or C ₃ H ₇ SO ₃ ^- a and, - (OR ³⁾ q- is - (OC
₂ H ₄ ) p−, and p is preferably 1 to 5. Also, - (R ⁶ O) q- is - (C ₂ H ₄ O) a q-, and it is preferable q is 1-10.

Further, examples of the antistatic agent that can be used in the present invention include a polymer having a repeating unit represented by the following formula (II-1).

[0032]

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In the above formula (II-1), R ¹¹ and R ¹² are each a monovalent organic group having 1 to 10 carbon atoms, for example, an alkyl group, a cycloalkyl group, an aryl group, an arachiral group and the like. In addition, the compound represented by the following formula (II-2) described in the above-mentioned JP-A No. 1-146931 may also be used. Among them, an alkyl group having 1 to 6 carbon atoms is preferable.

[0034]

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[0035] In the above formula ^{(II-2), R 13} ~R 15 each a monovalent organic group having 1 to 10 carbon atoms, for example alkyl, cycloalkyl, aryl, Arakiraru group, R ¹⁷ And R ¹⁸ each represent a divalent organic group having 2 to 10 carbon atoms, such as an alkylene group, a cycloalkylene group, an arylene group, an allylene group, a divalent aliphatic group containing a hetero atom (O, N, etc.), and the like. Can be Examples of the aliphatic _{group, -CH (OH) CH 2 -} , - CH 2 CH (OH) CH
_{2 -, - CH 2 CH 2} CH 2 NHCOCH 2 CH 2 CH 2 - and the like. Other examples include compounds described in the above-mentioned JP-A-3-255139, JP-A-4-288217, and the like, but are not limited thereto.

These can be used as homopolymers or as copolymers with other unsaturated monomers. When used by copolymerizing with another unsaturated monomer, the above repeating unit is preferably constituted by 50 mol% or more.
If it is less than 50 mol%, the antistatic property is insufficient. Other unsaturated monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate, methyl crotonate, glycidyl methacrylate , Acrylic methacrylate, acrylamide, methacrylamide, N-methylolacrylamide, ethylene, styrene, vinyl acetate, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, divinylbenzene, acrylic acid, methacrylic acid, maleic acid, fumaric acid, and the like. be able to.

The binder resin (F) to be added to the antistatic coating film is preferably at least one binder resin selected from a polyester resin (F-1) and an acrylic resin (F-2).

The acid components constituting the polyester resin (F-1) include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, Examples thereof include phenylindanedicarboxylic acid and dimer acid. Two or more of these components can be used. Further, it is also possible to use a small proportion of unsaturated polybasic acids such as maleic acid, fumaric acid, itaconic acid and the like and hydroxycarboxylic acids such as p-hydroxybenzoic acid and p- (β-hydroxyethoxy) benzoic acid together with these components. it can. The proportion of the unsaturated polybasic acid component or hydroxycarboxylic acid component is at most 10 mol%, preferably 5 mol% or less.

As the polyol component, ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylylene glycol, Examples thereof include methylolpropionic acid, glycerin, trimethylolpropane, poly (ethyleneoxy) glycol, poly (tetramethyleneoxy) glycol, and ethylene oxide adducts and propylene oxide adducts of bisphenol A represented by the following formula. . Two or more of these can be used.

[0040]

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[0041]

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Among such polyol components, ethylene glycol, ethylene oxide adduct of bisphenol A, propylene oxide adduct, and 1,4-butanediol are preferable, and ethylene glycol is more preferable.

The polyester resin (F-1) can be copolymerized with a small amount of a compound having a sulfonic acid group or a compound having a carboxylic acid group to facilitate aqueous liquefaction. , Which is preferred.

Examples of the compound having a sulfonate group include 5-Na sulfoisophthalic acid, 5-ammonium sulfoisophthalic acid, 4-Na sulfoisophthalic acid, 4-methylammonium sulfoisophthalic acid,
Na sulfoisophthalic acid, 5-K sulfoisophthalic acid,
Preferable examples include alkali metal sulfonic acid salts such as 4-K sulfoisophthalic acid, 2-K sulfoisophthalic acid, and sodium sulfosuccinic acid, and amine sulfonic acid salts. Examples of the compound having a carboxylic acid group include, for example, trimellitic anhydride, trimellitic acid, pyromellitic anhydride, pyromellitic acid, trimesic acid, cyclobutanetetracarboxylic acid, dimethylolpropionic acid, etc. Metal salts and the like. The free carboxyl group is converted to a carboxylate group by the action of an alkali metal compound or an amine compound after copolymerization.

The polyester resin (F-1) is used as a modified polyester copolymer, for example, a block polymer or a graft polymer obtained by modifying the polyester copolymer with an acryl, polyurethane, silicone, epoxy, phenol resin or the like. You can also.

The polyester resin (F-1) can be produced by a conventionally known or used polyester production technique. For example, 2,6-
Naphthalenedicarboxylic acid or its ester-forming derivative (particularly dimethyl ester), isophthalic acid or its ester-forming derivative (particularly dimethyl ester) and trimellitic anhydride are reacted with ethylene glycol and a propylene oxide adduct of bisphenol A to give a monomer or An oligomer is formed and then subjected to a polycondensation reaction under vacuum to obtain a copolymer having a predetermined intrinsic viscosity (the intrinsic viscosity measured at 35 ° C. using o-chlorophenol is preferably 0.2 to 0.8 dl / g). It can be produced by a method of forming a polymerized polyester and further reacting a free carboxy group with an alkali compound or an amine compound to form a salt. At that time, it is preferable to use a catalyst for accelerating the reaction, for example, an esterification or transesterification catalyst, a polycondensation catalyst, and the like, and various additives such as a stabilizer can be added.

In the present invention, the acrylic resin (F-) used as the binder resin (F) to be added to the antistatic coating film is used.
The constituent components of 2) include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, sodium acrylate, ammonium acrylate, 2-hydroxyethyl acrylate, methacrylic acid, methyl methacrylate,
Ethyl methacrylate, butyl methacrylate, sodium methacrylate, ammonium methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, acrylic methacrylate, sodium vinyl sulfonate,
Examples thereof include sodium methallylsulfonate, sodium styrenesulfonate, acrylamide, methacrylamide, and N-methylol methacrylamide.
These monomers can be used in combination with other unsaturated monomers such as styrene, vinyl acetate, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, and divinylbenzene.

Also, as the acrylic resin (F-2),
Modified acrylic copolymer, for example, the acrylic copolymer polyester, polyurethane, silicone, epoxy,
It can also be used as a block polymer modified with a phenol resin or the like, or as a graft polymer.

In the present invention, the antistatic coating film comprises at least an antistatic agent (E) composed of a polycationic polymer and at least one selected from the group consisting of a polyester resin (F-1) and an acrylic resin (F-2). The proportion of the antistatic agent (E) in the composition comprising one kind of binder resin (F) is 5 to 50 wt%, preferably 10 to 40 wt%. If this ratio is less than 5 wt%, the antistatic property is insufficient,
On the other hand, if it exceeds 50 wt%, the adhesion of the primer layer to the polyester film becomes insufficient, which is not preferable. The ratio of the binder resin (F) is 40 to 85% by weight, preferably 50 to 80% by weight. If the proportion is less than 40 wt%, the adhesion of the coating (primer layer) to the polyester film is insufficient, which is not preferable. On the other hand, when the content exceeds 85% by weight, the blocking property of the coated film deteriorates, which is not preferable.

[Aqueous coating liquid] The composition of the above-mentioned components for forming an antistatic coating film in the present invention is preferably applied as an aqueous coating liquid (using water as a medium). It is also possible to apply. Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol,
Ethanol, n-propanol, isopropanol and the like can be exemplified. These can be used alone or in combination of two or more.

In the present invention, the coating is preferably applied by using an aqueous coating liquid containing the above-mentioned composition. This aqueous coating liquid has good slipperiness on the surface of the coating and has good blocking resistance. It is preferable to add a lubricant within a range that does not impair properties such as adhesiveness, in order to improve the surface roughness. Preferred examples of the lubricant include fine particles such as polystyrene resin, acrylic resin, melamine resin, silicone resin, fluorine resin, urea resin, benzoguanamine resin, polyamide resin, and polyester resin. The fine particles of these resins may be thermoplastic or thermosetting as long as the fine particles are contained in the coating. The average particle size of the fine particles is 20 to 80.
nm, and the content is preferably 5 to 20 wt%.

Further, as long as the object of the present invention is not impaired, other surfactants, ultraviolet absorbers, pigments, lubricants,
Additives such as a blocking inhibitor, a crosslinking agent such as melamine, epoxy and aziridine, and other antistatic agents can be added.

In the present invention, in addition to the above components, other resins such as oxazoline resin, epoxy resin and melamine resin, other antistatic agents, coloring agents, surfactants, etc. An ultraviolet absorber or the like can be used.

[Lamination of Coating Film] In the present invention, a polyester film is coated with an ink-receiving layer easy-adhesion coating film on one surface and an antistatic coating film (hereinafter simply referred to as “coating film”) on the other surface.
May be abbreviated), for example, after applying an aqueous coating solution containing a component forming a coating film on a stretchable polyester film, drying, stretching, and heat-treating as necessary. Or after applying an aqueous coating solution containing a component for forming a coating film on the stretched polyester film, followed by drying.
The solid content concentration of this aqueous coating liquid is usually 30% by weight or less, and more preferably 10% by weight or less.

The above-mentioned stretchable polyester film is an unstretched polyester film, a uniaxially stretched polyester film or a biaxially stretched polyester film.
Of these, a longitudinally stretched polyester film uniaxially stretched in the film extrusion direction (longitudinal direction) is particularly preferred.

When the aqueous coating liquid is applied to the polyester film, the coating is carried out in a normal coating step, that is, in a step separated from the film manufacturing step in the biaxially stretched and heat-set polyester film. Easier and not preferred. From such a viewpoint, application in a clean atmosphere, that is, application in a film manufacturing process is preferable. According to this coating, the adhesion of the coating film to the polyester film is further improved.

As a coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brushing method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method and the like can be used alone or in combination. The coating amount is 0.5 to ²⁰ g per 1 m ² of the running film, and 1 to ²
10 g is preferred. The aqueous coating liquid is preferably used as an aqueous dispersion or an emulsion.

The stretchable polyester film coated with the aqueous coating solution is guided to a drying and stretching step, which can be performed under conditions conventionally accumulated in the art. As preferable conditions, for example, the drying condition is 9
0 to 130 ° C. × 2 to 10 seconds, and the stretching temperature is 90 to 1
30 ° C., stretching ratio 3-5 times in the vertical direction, 3-5 times in the horizontal direction,
If necessary, the length is 1 to 3 times in the vertical direction, and if heat-fixed, the temperature is 180 to 240 ° C. × 2 to 20 seconds.

The thickness of the polyester film after such treatment is preferably 50 to 150 μm, and the thickness of the coating film is preferably 0.02 to 3 μm.

[0060]

The present invention will be further described with reference to the following examples.
In addition, each characteristic value was measured by the following method.

1. Adhesion before printing On the coating surface of the polyester film, 70% by weight of spherical silica (average particle diameter 18μ, average pore diameter 200 angstrom, average pore volume 1.5cc / g), 30% by weight of polyvinyl alcohol (Kuraray PVA117) Is applied in a dry thickness of 20 μm, and a width 1
A 2.7 mm, 150 mm long scotch tape (No. 600, manufactured by 3M Co.) was adhered so as to prevent air bubbles from entering, and the top of the scotch tape was adhered by a manual load roll described in JIS C2701 (1975). Later, cut out to tape width. When the scotch tape was peeled from the sample thus prepared, the state of peeling of the ink image receiving layer from the polyester film was observed, and the adhesion was evaluated as follows. A: No peeling was observed, and the adhesion was good. B: Slight peeling is observed in the foreign matter portion. C: Peeling is remarkably observed.

[0062] 2. Adhesion after printing 70% by weight of spherical silica (average particle diameter 18μ, average pore diameter 200 angstrom, average pore volume 1.5cc / g) 70% by weight, polyvinyl alcohol (Kuraray PVA117) 30% by weight on the coating surface of the polyester film Is applied in a dry thickness of 20 μm, and an ink jet printer (PM-750 manufactured by EPSON) is applied thereon.
The image captured by a digital camera or the like in step C) is taken into a personal computer and printed, and the printed image has a width of 12.7 mm and a length of 1 mm.
50mm scotch tape (No. 6 manufactured by 3M)
00) to prevent air bubbles from entering.
After being leveled and adhered with a manual load roll described in C2701 (1975), it is cut out to a tape width. When the scotch tape was peeled from the sample thus prepared, the state of peeling of the ink image receiving layer from the polyester film was observed, and the adhesion was evaluated as follows. A: No peeling was observed, and the adhesion was good. B: Slight peeling is observed in the foreign matter portion. C: Peeling is remarkably observed.

3. Water-Resistant Adhesion The grease was impregnated with water from above the ink image-receiving layer, rubbed, and the number of rubbings before the ink-image-receiving layer was dropped was evaluated as described below. A: 50 times or more: Extremely good water resistance adhesiveness. B: 30 to 50 times: good water-resistant adhesion. C: Less than 30 times ··· Poor water resistance.

4. Surface resistivity (antistatic property) The surface resistivity of the sample film was measured by Takeda Riken Co., Ltd.
Using a specific resistance measuring instrument, measured temperature 23 ° C, measured humidity 60
%, The surface specific resistance (Ω / □) after one minute at an applied voltage of 500 V is measured. The surface specific resistance is 3 × 10
^It is preferably ¹² [Ω / □] or less, more preferably 3 × 10 ¹¹ or less.

5. Coefficient of friction According to ASTM D 1894-63, the surface and back of the film were combined using a slipper measuring device manufactured by Toyo Tester, and a static friction coefficient was measured by applying a load of 1 kg. If the coefficient of friction exceeds 0.6, the film transportability is impaired.

6. Blocking property Two films cut to a width of 50 mm are stacked, and 50 kg /
After treatment at 40 ° C. × 50% RH × 17 hours under a load of cm ² , the peel strength (g
/ 50 mm). Evaluation was made as follows by the value of the peel strength. Peel strength ≦ 10 g / 50 mm Good blocking property. 10 g / 50 mm <peel strength ≦ 30 g / 50 mm ... Slightly good blocking property. 30 g / 50 mm <peel strength: poor blocking property.

7. Surface energy W. A. Zisman: "Contact Augl
e, Wetability and Adhesi
on ", Am. Chem. Soc., (196
According to 4), the measured critical surface tension γc was used as the surface energy.

8. Secondary transition point Thermal Analyst 200 manufactured by DuPont
It was measured at a heating rate of 20 ° C./min with a type 0 differential calorimeter.

9. Intrinsic viscosity The viscosity of the solution with orthochlorophenol solvent is 35 ℃
Was measured and determined.

10. Gloss Gs (60 °) Gloss is measured according to JIS Z 8741-1962 using a gloss meter GM-3D manufactured by Murakami Color Research Laboratory.
The measurement angle is 60 °, the number of measurements is n = 5, and the average value is the value of the gloss Gs (60 °).

11. Light transmittance The light transmittance was measured using a HR-100 haze meter manufactured by Murakami Color Research Laboratory in accordance with ASTM D1003.

12. Heat shrinkage The shrinkage after heat treatment of the polyester film at 150 ° C. for 30 minutes was measured at a distance between the gauge points of 30 cm.

13. Sharpness The polyester film coated with the ink image-receiving layer was printed on an inkjet printer (PM-
The image taken with a digital camera or the like at 750C) was taken into a personal computer, printed, and the sharpness of the printed matter was visually observed, and evaluated as follows. A: Printing is extremely clear and excellent.... B: Printing is excellent in sharpness. C: The printing is unclear and the sharpness is poor. The sharpness is poor.

14. Conveyance The polyester film coated with the ink image-receiving layer is printed on an inkjet printer (PM-
At 750C), images taken by a digital camera or the like were taken into a personal computer, and 50 sheets were continuously printed, and whether or not films could be continuously printed was evaluated as follows. A: There was no clogging even when 50 sheets were continuously fed, and printing was possible. B: There was no clogging even when 45 sheets were continuously fed, and printing was possible. The transportability was slightly poor. C: 45 sheets or less, continuous paper cannot be fed and printing cannot be performed. Poor transportability.

Example 1 A polyester (intrinsic viscosity: 0.62) comprising a terephthalic acid component and an ethylene glycol component was melt-extruded onto a rotating cooling drum maintained at 20 ° C. to form an unstretched film. After the stretched film is stretched 3.6 times in the machine axis direction, the aqueous coating solution for the ink-receiving layer easy-adhesion layer on one side, a copolymerized polyester as the aqueous binder, terephthalic acid [60 mol%] as an acid component, isophthalic acid [ 36 mol%] and 5-Na sulfoisophthalic acid [4 mol%], and a glycol component composed of ethylene glycol [60 mol%] and neopentyl glycol [40 mol%] (Tg
= 30 ° C, hereinafter simply referred to as [H]) 51% by weight, polyvinyl alcohol 20% by weight having a saponification degree of 86 to 89% by mole, 10% by weight of crosslinked acrylic resin particles having an average particle diameter of 40 nm, the following formula (I-1) 10% by weight of compound (O) and 9% by weight of polyoxyethylene lauryl ether
An aqueous coating solution having a solid content concentration of 4% by weight was applied by a roll coater.

[0076]

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At the same time, on the other side, terephthalic acid (22 mol%), isophthalic acid (1 mol%), 2,6-naphthalenedicarboxylic acid (65 mol%), 4,4′- Diphenyl dicarboxylic acid (12 mol%), ethylene glycol (75 mol%)
%), 1,4-cyclohexanedimethanol (10 mol
1%), a copolyester made from neopentyl glycol (15 mol%) (Tg = 80 ° C., average molecular weight = 21,500) (F-1) 75 wt%, a high polymer represented by the following formula (II-3) Molecular antistatic agent (E) 20wt
% And polyoxyethylene lauryl ether 5wt%
4 g / m ^{2 of} a 10 wt% aqueous coating liquid having a solid content composition of
(Wet) with a roll coater. Next, the vertically stretched film coated with the aqueous coating solution was stretched 4 times in the transverse direction while drying, and further heat-set at 230 ° C. to a thickness of 1
A 00 μm biaxially stretched film was obtained.

[0078]

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The film thickness of the ink image-receiving layer easy-adhesion layer in this film was 0.05 μm, and the surface energy was 59 mN /
m, the heat shrinkage was 0.9% in the vertical direction and 0.2% in the horizontal direction. The coating thickness of the coating layer of the antistatic coating was 0.1 μm. Table 1 shows the properties of this film.

Comparative Example 1 Table 1 shows the properties of the biaxially stretched polyester film obtained in the same manner as in Example 1 except that the aqueous coating solution was not applied.

Comparative Example 2 Table 1 shows the properties of the biaxially stretched polyester film obtained in the same manner as in Example 1 except that the aqueous coating solution for the ink-receiving layer on the one surface was easily applied.

Comparative Example 3 Table 1 shows the properties of the biaxially stretched polyester film obtained in the same manner as in Example 1 except that the aqueous coating solution for a single-sided antistatic coating film was not applied.

[Examples 2 to 7] A biaxially stretched polyester film was obtained in the same manner as in Example 1 except that the kind and ratio of the ink image-receiving layer coating for easy adhesion were changed as shown in Table 1. Table 1 shows the properties of this film.

[0084]

[Table 1]

As is clear from the results shown in Table 1, the ink-receiving layer easily adhesive polyester film of the present invention is excellent in adhesiveness, antistatic property and transportability.

In Table 1, types H and J (Note 1) of copolyester (A) indicate the following compounds. H: terephthalic acid [60 mol%] / isophthalic acid [36
Mol%] · 5-Na sulfoisophthalic acid [4 mol%] /
Copolymer of ethylene glycol [60 mol%] / neopentyl glycol [40 mol%] (Tg = 30 ° C.) J: 2,6-naphthalene dicarboxylic acid [20 mol%]
Isophthalic acid [76 mol%] 5-K sulfoterephthalic acid [4 mol%] / ethylene glycol [50 mol%]
Neopentyl glycol [50 mol%] copolymer (Tg
= 42 ° C)

In Table 1, types P, Q and R (Note 2) of the water-soluble polymer (B) indicate the following compounds. P: polyvinyl alcohol having a saponification degree of 86 to 89 mol% Q: polyvinyl alcohol having a saponification degree of 74 to 78 mol% R: polyvinyl alcohol having a saponification degree of 92 to 95 mol%

In Table 1, the types M and N (Note 3) of the fine particles (C) indicate the following compounds. M: Crosslinked acrylic particles having an average particle size of 40 nm N: Colloidal silica particles having an average particle size of 80 nm

In Table 1, types O and S (Note 4) of compound (D) indicate that they are compounds represented by the following formulas (I-1) and (I-2).

[0090]

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[0091]

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[Examples 8 to 11 and Comparative Examples 4 and 5] The type of the copolyester (A) of the aqueous coating solution of the coating for the ink-receiving layer was easily changed as shown in Tables 2 and 3. A biaxially stretched polyester film was obtained in the same manner as in Example 1 except that copolyesters having different Tg were used. Table 2 shows the properties of the obtained film.

[0093]

[Table 2]

[0094]

[Table 3]

As is clear from the results shown in Table 2, the ink-receiving layer easily adhesive polyester film of the present invention is excellent in blocking resistance, adhesiveness, antistatic property and transportability.

[Examples 12 to 16 and Comparative Examples 6 to 13]
The types and ratios of the copolyester (A), the water-soluble polymer (B), the fine particles (C) and the compound (D) in the aqueous coating liquid of the coating agent for the ink-receiving layer were easily changed as shown in Table 4. Except for the above, a biaxially stretched polyester film was obtained in the same manner as in Example 1. Table 4 shows the properties of the obtained film.

[0097]

[Table 4]

As is clear from the results shown in Table 4, the ink-receiving layer easily adhesive polyester film of the present invention is excellent in adhesiveness, antistatic property and transportability.

[Examples 17 and 18 and Comparative Examples 14 and 1
5] A biaxially stretched polyester film was obtained in the same manner as in Example 1, except that the particle size of the fine particles (C) in the aqueous coating solution of the coating composition for the ink image receiving layer and the adhesive layer was changed as shown in Table 5. .
Table 5 shows the properties of the obtained film.

[0100]

[Table 5]

As apparent from the results shown in Table 5, the ink-receiving layer easily adhesive polyester film of the present invention has excellent blocking resistance.

[Examples 19 and 20 and Comparative Examples 16 and 1
7] The ratios of the copolyester (A), the water-soluble polymer (B), the fine particles (C) and the compound (D) in the aqueous coating solution of the coating agent for the ink image-receiving layer and the adhesive layer were changed as shown in Table 6. Except for the above, a biaxially stretched polyester film was obtained in the same manner as in Example 1. Table 6 shows the properties of the obtained film.

[0103]

[Table 6]

As is clear from the results shown in Table 6, the ink-receiving layer easily adhesive polyester film of the present invention is excellent in adhesiveness, antistatic property and transportability.

Example 21 The copolymerized polyester (F-1) of the aqueous coating solution for an antistatic coating film of Example 1 was prepared by adding methyl methacrylate (30 mol%) and ethyl acrylate (55
mol%), acrylonitrile (10 mol%) and N
-Acrylic copolymer prepared from methylol methacrylamide (5 mol%) (number average molecular weight: 25800)
0) Except changing to (F-2), a biaxially stretched polyester film was obtained in exactly the same manner as in Example 1. Table 7 summarizes the properties of the obtained film.

[Example 22] A polycationic polymer having the antistatic agent (E) of the aqueous coating solution for an antistatic coating film of Example 21 and a plurality of pyrrolidium rings having the following structure in the main chain (number average molecular weight: 29000; A biaxially stretched polyester film was obtained in exactly the same manner as in Example 1, except that the polymer was changed to the polymer represented by the following formula (II-4). Table 7 summarizes the properties of the obtained film.

[0107]

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Example 23 The antistatic agent (E) of the aqueous coating solution for an antistatic coating film of Example 21 was replaced with a polycation polymer having the following structure (number-average molecular weight: 6000;
A biaxially stretched polyester film was obtained in exactly the same manner as in Example 1, except that the polymer was changed to the polymer shown in 5).
Table 7 summarizes the properties of the obtained film.

[0109]

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Example 24 A polyester (intrinsic viscosity: 0.62) comprising a terephthalic acid component and an ethylene glycol component was melt-extruded onto a rotating cooling drum maintained at 20 ° C. to form an unstretched film. After the stretched film is stretched 3.6 times in the machine axis direction, the aqueous coating solution for the ink-receiving layer easy-adhesion layer on one side, a copolymerized polyester as the aqueous binder, terephthalic acid [60 mol%] as an acid component, isophthalic acid [ 36 mol%] and 5-Na sulfoisophthalic acid [4 mol%], and a glycol component composed of ethylene glycol [60 mol%] and neopentyl glycol [40 mol%] (Tg
= 30 ° C: [H]) 51% by weight, 20% by weight of polyvinyl alcohol having a degree of saponification of 86 to 89% by mole, average particle size 40
10% by weight of crosslinked acrylic resin particles of
A composition comprising 10% by weight of the compound (O) represented by 1) and 9% by weight of polyoxyethylene lauryl ether,
An aqueous liquid having a solid concentration of 4% by weight was applied using a roll coater.

Next, the vertically stretched film coated with the aqueous coating solution was stretched 4 times in the transverse direction while drying, and further heat-set at 230 ° C. to obtain a 100 μm thick biaxially stretched film. In this film, the coating thickness of the ink image-receiving layer easy-adhesion layer is 0.1.
The surface energy was 59 mN / m, the heat shrinkage was 0.9% in the vertical direction, and 0.2% in the horizontal direction. On the opposite side of the ink image receiving layer easy adhesion layer of the obtained sample, as antistatic coating film, terephthalic acid (22 mol%), isophthalic acid (1 mol%), 2,6-naphthalenedicarboxylic acid (65 mol%), 4 , 4'-diphenyldicarboxylic acid (12mol%), ethylene glycol (75mo
1%), 1,4-cyclohexanedimethanol (10 m
ol%), a copolyester made from neopentyl glycol (15 mol%) (Tg = 80 ° C., average molecular weight = 21,500) (F-1) 75 wt%, a high polymer represented by the formula (II-3) Molecular antistatic agent (E) 20wt
% And polyoxyethylene lauryl ether 5wt%
15% of isopropanol as a solvent was added, and a coating solution having a solid content of 10% by weight was coated at 6 g / m ² (we
After coating with a gravure coater with the coating amount of t), using a drying furnace, the film tension in the furnace is 300 g / m ² , and the temperature is 17
It was dried at 0 ° C. for 20 seconds to obtain a biaxially stretched polyester film coated with a 0.5 μm-thick antistatic coating film.
Table 7 summarizes the properties of this film.

Example 25 A biaxially stretched polyester film was obtained in the same manner as in Example 24 except that the antistatic agent of the antistatic coating film of Example 24 was changed to sodium polystyrene sulfonate. Table 7 summarizes the properties of this film.

Example 26 A composition comprising 90% by weight of a polyester (having an intrinsic viscosity of 0.62) comprising a terephthalic acid component and an ethylene glycol component and 10% by weight of titanium oxide was placed on a rotary cooling drum maintained at 20 ° C. A non-stretched film is melt-extruded, and then the unstretched film is stretched 3.6 times in the machine axis direction on one surface of a uniaxially stretched film. As an aqueous binder, a copolymerized polyester (acid component containing terephthalic acid [60 mol% ], Isophthalic acid [36
Mol%], 5-Nasulfoisophthalic acid [4 mol%], and a glycol component composed of ethylene glycol [60 mol%] and neopentylglycol [40 mol%]: Tg = 30 ° C., [H]) 51
20% by weight of polyvinyl alcohol having a saponification degree of 86 to 89% by mole, 10% by weight of crosslinked acrylic resin particles having an average particle diameter of 40 nm, 10% by weight of the compound (O) represented by the formula (I-1), and An aqueous coating solution having a composition of 9% by weight of oxyethylene lauryl ether and having a solid content of 4% by weight was applied by a roll coater.

At the same time, on the other side of the uniaxially stretched film, terephthalic acid (22 m
ol%), isophthalic acid (1 mol%), 2,6-naphthalenedicarboxylic acid (65 mol%), 4,4'-diphenyldicarboxylic acid (12 mol%), ethylene glycol (75 mol%), 1,4-cyclohexanedimethanol (10 mol%), neopentyl glycol (1
5mol%) (Tg
= 80 ° C, average molecular weight = 21,500) (F-1) 75
4 g / m ² (wet) of a 10 wt% aqueous coating liquid having a solid content composition comprising 20 wt% of a polymer antistatic agent (E) represented by the above formula (II-3) and 5 wt% of polyoxyethylene lauryl ether represented by the above formula (II-3). With a roll coater. The uniaxially stretched film coated with the aqueous coating solution was stretched 4 times in the transverse direction while drying, and further heat-set at 230 ° C. to obtain a biaxially stretched film having a thickness of 100 μm. The film thickness of this film is 0.05 μm and the surface energy is 5
9 dyne / cm, glossiness was 60, light transmittance was 3%, and clearness, adhesion, antistatic properties, and transportability were good.

[0115]

[Table 7]

[0116]

Industrial Applicability The present invention relates to a polyester film having an ink-receiving layer which is easy to adhere to, and more particularly to an excellent concealing property, excellent water-resistant adhesion to an aqueous ink-receiving layer of an ink jet printer or the like, and excellent transportability and antistatic property. And an ink-receiving layer which is useful for an image-receiving paper.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H086 BA12 BA15 BA19 BA24 BA31 BA35 BA36 BA41 BA45 4F006 AA35 AB12 AB20 AB34 AB35 AB43 BA01 BA07 CA01 DA04 4F100 AH02B AH02H AK21B AK25C AK41B CA18C CA22C CC00B CC00C DE01B DE01H EJ38A GB90 HB00 JA03A JA05B JA20B JG03C JL10 JL11B JN02 JN21 YY00 YY00A YY00B YY00C 4J038 CE022 CG002 DB152 DD001 KA09 KA20 MA13 NA20 PC08

Claims (7)

[Claims] 1. A laminated film in which an ink-receiving layer easy-adhesion coating film is provided on one surface of a polyester film and an antistatic coating film is provided on the other surface, wherein the ink-image receiving layer easy-adhesion coating film is secondarily transferred. Copolyester (A) having a point of 20 to 90 ° C, 30 to 80% by weight, saponification degree 80 to 90 mol%
15 to 45% by weight of polyvinyl alcohol (B), 3 to 25% by weight of fine particles (C) having an average particle diameter of 20 to 80 nm, and 5 to 20% by weight of a compound (D) represented by the following formula (I).
And a surface energy of the ink-receiving layer easy-adhesion coating film is 50 to 70 mN / m. Embedded image 2. The antistatic coating film is selected from the group consisting of 5 to 50% by weight of an antistatic agent (E) composed of a polycation polymer, a polyester resin (F-1) and an acrylic resin (F-2). The ink-receiving layer easily adhesive polyester film according to claim 1, which is a coating film containing 40 to 85% by weight of at least one binder resin (F). 3. An antistatic coating film comprising 40 to 85% by weight of at least one binder resin (F) selected from a polyester resin (F-1) and an acrylic resin (F-2); The ink image-receiving layer according to claim 2, wherein the coating film contains 5 to 50% by weight of an antistatic agent (E) and 5 to 15% by weight of a surfactant (G) having a repeating unit represented by the following formula as a main component. Easy adhesion polyester film. Embedded image (However, R ¹ and R ² in the formula are each H or CH ₃ , R ³ is an alkylene group having 2 to 10 carbon atoms, R ⁴ and R ⁵ are each a saturated hydrocarbon group having 1 to 5 carbon atoms, R ⁶ has 2 to 1 carbon atoms
0 is an alkylene group, p is a number from 1 to 20, q is a number from 1 to 40, Y ^- is a halogen ion, mono- or polyhalogenated alkyl ion, nitrate ion, sulfate ion, alkyl sulfate ion, sulfonate ion or alkyl. It is a sulfonate ion. ) 4. The polyester film according to claim 1, wherein the polyester film has a glossiness of 50 or more, a light transmittance of 20% or less, and is white. 5. A polyester film having a viscosity of 3 ° C. at 150 ° C.
The polyester film according to claim 1, which is a biaxially stretched film having a heat shrinkage of 1% or less when held for 0 minutes. 6. The polyester film having a light transmittance of 2
5. The polyester film according to claim 4, wherein the polyester film is 0% or less, is white, and is further provided with an aqueous ink image-receiving layer on the ink-image-receiving layer easily adhesive coating film. 7. The polyester film according to claim 6, which is used for an image receiving paper for an ink jet printer.