JP3098395B2 - Easy adhesion white polyester film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easily-adhesive white polyester film, and more particularly to an easily-adhesive white polyester film having excellent adhesion and antistatic properties and improved non-transfer properties of a magnetic layer.

[0002]

2. Description of the Related Art A white film made of an aromatic polyester containing a white pigment such as titanium oxide is widely used for magnetic cards, printing materials, etc. However, a common problem with plastic films is that static electricity is easily generated and film formation is difficult. Process,
There are drawbacks that various troubles are liable to occur in the processing step and further during use of the product, and that the adhesion of the magnetic paint or the printing ink is poor.

In particular, thick white polyester films are used for magnetic cards such as telephone cards, prepaid cards and the like. Due to the difficulty in adhesion, application of a primer has also been proposed.

Hitherto, as a method for improving the adhesiveness of a polyester film, many methods have been proposed in which a primer layer (coating) made of a synthetic resin is previously formed on a film surface. For example, those using an ester-based polymer (JP-A-60-248232), those using an acrylic-based polymer (JP-A-62-204941), those using a urethane-based polymer (Japanese Patent Publication No. 5-51018), and those based on an ester Using polymer and acrylic polymer (Japanese Patent Application Laid-Open No. 58-1)
24651, JP-A-6-177790) have been proposed.

However, in the primer layer formed by these methods, a magnetic paint is applied on one side in a magnetic card processing step, and when this is aged in a roll state, one layer of the magnetic layer (magnetic recording layer) is obtained. Since the portion causes transfer (blocking) to the primer layer on the opposite surface, and often deteriorates the production efficiency, it has been difficult to satisfy both the adhesiveness to the magnetic layer and the non-transferability. Also,
The film is generally easily charged, and has a disadvantage that various troubles are likely to occur in a film forming process, a processing process, and a use of a product.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have studied a polyester film having a primer layer composed of a polyester resin, an acrylic resin and a compound containing a sulfonate group, and further examined the adhesiveness and non-transferability of a magnetic layer. As a result, it has been found that the secondary transition point of the binder component constituting the primer layer is involved. further,
As a result of studying to improve this point, it was found that by forming the primer layer using a binder having a specific property and a secondary transition point, non-transferability can be exhibited without impairing the adhesive force to the magnetic layer. And arrived at the present invention.

[0007]

That is, the present invention provides a white aromatic polyester film having a thickness of 20 μm or more, which has (1) an average particle diameter of 100 nm or less and a secondary transition point of 50 to 120 ° C.
10 to 60% by weight of an aromatic polyester resin, (2) 10 to 60% by weight of an acrylic copolymer having an average particle diameter of 100 nm or less, and a secondary transition point of 50 to 120 ° C, and (3) in the molecule. An easy-adhesion white polyester film coated with an easy-adhesion film having a dry film thickness of 0.02 to 2 μm using a coating solution containing a composition comprising 5 to 60% by weight of a substance having a sulfonate group.

In the present invention, the aromatic polyester constituting the white film is a crystalline linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. is there. As specific examples of such polyester, polyethylene terephthalate, polyethylene isophthalate,
Polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), polyethylene
Examples thereof include 2,6-naphthalenedicarboxylate. These include copolymers or blends of these with small proportions of other resins. Among them, polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate are particularly preferred.

These polyesters are white pigments,
For example, it contains titanium oxide and / or barium sulfate. In addition, inorganic fillers such as silicon oxide, aluminum oxide, magnesium oxide, calcium carbonate, kaolin, talc, etc., organic fillers such as crosslinked polystyrene resin, crosslinked acrylic resin, urea resin, melamine resin, polyethylene, polypropylene, ethylene -Other resins such as propylene copolymers and olefinic ionomers, antioxidants, ultraviolet absorbers, fluorescent brighteners, and the like can be contained as necessary.

The white polyester film in the present invention contains 5 to 20% by weight of a white pigment such as titanium oxide and barium sulfate, and the surface gloss can be arbitrarily selected.

In the present invention, the white polyester film is preferably a biaxially stretched film, and has a thickness of
20 μm or more, preferably 50 to 500 μm, particularly preferably 7 μm
5 to 300 μm. If the thickness is less than 20 μm, the film is weak and unsuitable. On the other hand, if the film is too thick, for example, if it exceeds 500 μm, the film-forming properties tend to be poor.

In the present invention, the primer layers (easily adhesive films) provided on both sides of the white polyester film are (1)
Aromatic polyester resin having an average particle size of 100 nm or less and a secondary transition point of 50 to 120 ° C. 10 to 60% by weight, (2) an average particle size of 100
nm or less, a coating liquid containing a composition consisting of 10 to 60% by weight of an acrylic copolymer having a secondary transition point of 50 to 120 ° C and 5 to 60% by weight of a substance having a sulfonate group in a molecule (3). It is formed by applying to a required surface of the film and drying by heating. This heating and drying is performed at a temperature at which the coating forms a uniform thin film.

In the present invention, the acid component forming the aromatic polyester resin (1) constituting the coating liquid includes terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid , Adipic acid, sebacic acid, phenylindanedicarboxylic acid, dimer acid and the like. 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 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.

The polyol component forming the aromatic polyester resin (1) includes ethylene glycol,
1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6
-Hexanediol, 1,4-cyclohexanedimethanol, xylylene glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, poly (ethyleneoxy) glycol, poly (tetramethyleneoxy) glycol, and bisphenol A represented by the following formula Of ethylene oxide and propylene oxide

[0015]

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[0016]

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[However, n + m = 2 to 10, ph = phenyl group] and the like. Two or more of these can be used.

Of these polyol components, ethylene glycol, ethylene oxide adducts and propylene oxide adducts of bisphenol A, and 1,4-butanediol are preferred. Further, ethylene glycol and bisphenol A ethylene oxide adducts and propylene oxide adducts are preferable. preferable.

The aromatic polyester resin may be copolymerized with a compound having a small amount of a sulfonic acid group or a compound having a carboxylic acid group in order to facilitate aqueous solution or water dispersion. Yes, that 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,
Examples thereof include alkali metal salts of sulfonic acid such as 4-K sulfoisophthalic acid, 2-K sulfoisophthalic acid, and sodium sulfosuccinic acid, and amine salts of sulfonic acid.

Examples of the compound having a carboxylate group include trimellitic anhydride, trimellitic acid, pyromellitic anhydride, pyromellitic acid, trimesic acid, cyclobutanetetracarboxylic acid, dimethylolpropionic acid, and the like, Alkali 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.

Further, as the aromatic polyester resin (1), a modified polyester copolymer, for example, a polyester copolymer is prepared by using acrylic, polyurethane, silicone, epoxy,
A block polymer or a graft polymer modified with a phenol resin or the like can also be used.

Aromatic polyester resin in the present invention
(1) can be produced by a conventionally known or used polyester production technique. For example, 2,6-naphthalenedicarboxylic acid or its ester-forming derivative (especially dimethyl ester), isophthalic acid or its ester-forming derivative (especially dimethyl ester), and trimellitic anhydride are adducted with propylene oxide of ethylene glycol and bisphenol A. To form a monomer or oligomer, followed by a polycondensation reaction under vacuum to obtain a polyester having a predetermined intrinsic viscosity (the intrinsic viscosity measured at 35 ° C. using o-chlorophenol is preferably 0.2 to 0.8). It can be manufactured by the method described below. 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.

The secondary transition point (Tg) of the aromatic polyester resin (1) needs to be 50 to 120 ° C. This T
If g is less than 50 ° C., the transfer of the magnetic layer is likely to occur.

In the present invention, the acrylic copolymer (2) constituting the coating liquid comprises acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, sodium acrylate, ammonium acrylate, Hydroxyethyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, sodium methacrylate, ammonium methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, acrylic methacrylate, sodium vinyl sulfonate, sodium methallylsulfonate, Examples thereof include sodium styrenesulfonate, acrylamide, methacrylamide, N-methylol methacrylamide, and the like. These monomers can be used in combination with other unsaturated monomers such as styrene, vinyl acetate, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, and divinylbenzene.

As the acrylic copolymer (2), a modified acrylic copolymer, for example, a block polymer or a graft polymer obtained by modifying an acrylic copolymer with polyester, polyurethane, silicone, epoxy, phenol resin or the like is used. Can also.

The acrylic copolymer (2) in the present invention must have a secondary transition point (Tg) of 50 to 120 ° C. If the Tg is less than 50 ° C., the transfer of the magnetic layer tends to occur. As the substance (3) having a metal sulfonate group in the molecule constituting the coating liquid in the present invention, conventionally known low molecular weight substances and high molecular weight substances, for example, metal alkyl sulfonate, metal alkylbenzene sulfonate, Examples thereof include a metal salt of an alkyl diphenyl ether disulfonic acid, a polyester copolymer having a sulfonic acid metal base, an acrylic copolymer, and a vinyl copolymer. These alone,
Alternatively, a plurality of them can be used in combination.

In the present invention, the aromatic polyester resin
(1) and the acrylic copolymer (2) are dissolved or dispersed in the coating solution solvent, when dispersed, the average particle size must be 100 nm or less, more preferably 80 nm
It is as follows. If the average particle size exceeds 100 nm, transfer of the magnetic layer is likely to occur. In this case aromatic polyester resin
It is preferable that (1) and the acrylic copolymer (2) are each separately dispersed in a solvent in advance to adjust the average particle diameter. Here, the average particle size is defined as an aqueous dispersion or an aqueous solution, which is referred to as a fine particle analyzer (PACIFIC SCIE
It was measured using NTIFIC's NICOMP MODEL 200E).

In the present invention, the aromatic polyester resin
(1), the composition of the acrylic copolymer (2) and the substance (3) having a metal sulfonate group in the molecule (3), the proportion of the aromatic polyester resin (1) is 5 to 70% by weight, preferably
10 to 60% by weight. If this proportion exceeds 70% by weight, the adhesion of the primer layer to the printing ink will be insufficient, while if it is less than 5% by weight, the adhesion of the primer layer to the polyester film will be insufficient. The proportion of the substance (3) having a metal sulfonate group in the molecule is 3 to 50% by weight, preferably 10 to 40% by weight. If the proportion is less than 3% by weight, the antistatic property is insufficient, while if it exceeds 50% by weight, the adhesion of the primer layer to the polyester film is insufficient, which is not preferable.

The coating liquid of the present invention, particularly the aqueous coating liquid, includes:
It is preferable to include a wetting agent in order to improve the wettability to the aromatic polyester film. As a wetting agent, the surface tension of the coating liquid, particularly the aqueous coating liquid, is 50 dyne / cm or less,
Surfactants such as anionic surfactants, cationic surfactants, and nonionic surfactants, which are preferably 40 dyne / cm or less, are preferred, for example, polyethylene oxide / polypropylene oxide block copolymer, polyoxyethylene alkyl phenyl ether. , Polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl sulfonate, alkyl sulfate, alkylbenzene sulfonate, alkyl diphenyl ether disulfonate,
Alkyl sulfosuccinate, quaternary ammonium chloride salt, quaternary ammonium ethyl sulfate, alkylamine hydrochloride and the like can be mentioned. The amount of the wetting agent is preferably 2 to 30% by weight, more preferably 3 to 20% by weight based on the total solids of the primer.

The coating liquid in the present invention can use an organic solvent as a solvent. Examples of the solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran,
Examples thereof include dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol, ethanol, n-propanol and isopropanol. These can be used alone or in combination of two or more.

In the present invention, for example, other antistatic agents can be used as long as the object of the invention is not impaired. For example, anionic polymers such as anionic, cationic, nonionic, betaine, and quaternary ammonium bases, ionene polymers, phosphate compounds, phosphate compounds, and the like, and metals such as tin oxide and antimony oxide An oxide, a metal alkoxide such as alkoxysilane, alkoxytitanium, alkoxyzirconium and the like, a derivative thereof, one kind selected from coated carbon, coated silica and the like, or a combination of two or more kinds can be used.

Further, as long as the object of the present invention is not impaired, for example, ultraviolet absorbers, antioxidants, pigments, organic fillers, inorganic fillers, lubricants, antiblocking agents,
Other additives such as crosslinking agents such as melamine, epoxy, aziridine and the like can be mixed.

In the present invention, the solid content of the coating solution is usually
It is preferably at most 30% by weight.

In the present invention, a (primer) coating solution containing the above-mentioned components is applied to both sides of a white polyester film, and the film is preferably a white polyester film before the crystal orientation is completed.

As the white polyester film before the completion of the crystal orientation, an unstretched film obtained by heat-melting the polyester to form a film, or an unstretched film is oriented in either the machine direction or the transverse direction. Uniaxially stretched film, one stretched and oriented at a low magnification in two directions of longitudinal and transverse directions (biaxially stretched film before being finally stretched in the longitudinal or transverse direction to complete orientation crystallization) and the like. Examples can be given.

As a method of applying the coating liquid to the polyester film, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a microgravure coating method, a reverse coating method, a roll brushing method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method, or the like may be applied alone or in combination. When this aqueous coating liquid is used, a small amount of an organic solvent may be contained for the purpose of assisting the stability of the coating liquid or the coatability of the coating liquid. The amount of coating is the running film 1
m ² per 3 to 50 g, more 5~40g is preferred. The thickness of the final dried coating film (coating) needs to be 0.02 to 2 μm, and preferably 0.05 to 1 μm. The thickness of the coating
If it is less than 0.02 μm, sufficient antistatic properties cannot be obtained. On the other hand, if it exceeds 2 μm, the slipperiness is undesirably reduced.

The coating is performed on both sides of the film. After the application, the coating is heated and dried to form a uniform coating film.

In the present invention, the magnetic layer (magnetic recording layer)
Although not particularly limited, the following can be mentioned as typical examples. That is, as magnetic powder, γ-Fe ₂
O ₃ , CrO ₂ , Co-γ-Fe ₂ O ₃ , Fe ₃ O ₄ , BaO
6FeO ₃ , metal magnetic powder, and as binder, vinyl resin such as vinyl acetate, polyvinylidene chloride, PVC, acrylic resin, rubber resin such as acrylonitrile / butadiene copolymer, cellulose such as nitrocellulose, epoxy Resin, phenolic resin, polyurethane resin, and if necessary, dispersant, lubricant,
Examples thereof include a mixture of a stabilizer, an antistatic agent such as carbon, a plasticizer, and the like.

The printing ink layer in the present invention is not particularly limited, but preferably includes conventionally known ultraviolet-curable printing inks, electron beam-curable inks, and heat-sensitive recording inks.

[0041]

EXAMPLES The present invention will be further described below with reference to examples. The characteristics in the examples were obtained by the following method.

1. Transferability of Magnetic Layer The following paint for evaluation is applied to a sample film using a Meyer bar so that the thickness after drying is about 5 μm, and dried at 100 ° C. for 3 minutes. This magnetic surface and the primer-coated surface of another sample are overlapped, and under a pressure of 50 kg / cm ² ,
Aging was performed at 50 ° C. for 17 hours, and then the coloring of the primer-coated surface when this was peeled was visually determined.も の indicates no change on the surface, 、 indicates slight coloring, and X indicates completely colored.

[Evaluation paint] In terms of solid content, 25 parts by weight of urethane resin Nipporan 2304 (manufactured by Nippon Polyurethane), 50 parts by weight of vinyl chloride / vinyl acetate resin ESREC A (manufactured by Sekisui Chemical), dispersant Ratio P (manufactured by RIKEN Vitamin) 1) 1 part by weight and magnetic agent CTX-860 (made by Toda Chemical) 50
0 parts by weight is dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to make a 40% solution, and the mixture is dispersed with a sand grinder for 2 hours. Then the crosslinking agent Coronate L
Add 25 parts by weight (in terms of solid content) and stir well to obtain a magnetic paint.

2. Adhesive force of magnetic paint The paint for evaluation described above was applied to a sample film with a Meyer bar so that the thickness after drying was about 5 μm.
Dry for minutes. After aging at 60 ° C for 24 hours, Scotch tape No. 600 (manufactured by 3M) was applied with a width of 12.7 mm and a length of 15 cm to prevent air bubbles from entering.
It is leveled and adhered with a manual load roll described in SC2701 (1975), and cut into a tape width. The strength when this is peeled 180 degrees is measured.

3. Adhesive strength of UV ink A UV curable printing ink (Flash Dry FD Carton P Beniro, manufactured by Toyo Ink) is applied to the sample film as RI.
After printing with a tester (manufactured by Akira Seisakusho), curing is performed with a medium pressure mercury lamp (80 W / cm, single lamp; manufactured by Nippon Battery) UV curing device to form a UV ink layer having a thickness of 4 μm. A cellophane tape (18 mm wide; made by Nichiban) is applied to the UV ink layer to a length of 15 cm, a constant load is applied on the UV ink layer with a 2 kg hand-operated load roll, the film is fixed, and one end of the cellophane tape is fixed at 90 °. The peel adhesion is evaluated by peeling in the direction. The adhesiveness is evaluated based on the following five criteria. 5: The ink layer is not peeled at all. 4: Less than 3% of the ink layer is peeled. 3: 3 to 10% of the ink layer is peeled. 2: 10 to 30% of the ink layer is peeled. 1: 30% or more of the ink. Delamination

4. Antistatic property The antistatic property is determined by measuring the surface resistivity of the sample film using a resistivity measurement device manufactured by Takeda Riken Co., Ltd. at a measurement temperature of 23 ° C and a measurement humidity of 65%, and after 1 minute at an applied voltage of 500 V for 1 minute. Measure the resistance value (Ω / □). 1 × 10 ¹¹ Ω / □ or less is preferable.

5. Blocking property After cutting the primer coated surface of the polyester film and the primer uncoated surface, cut into 5cm x 10cm squares,
6 kg / c for 17 hours in an atmosphere of 50 ° C. and 70% RH
A pressure of m ² is applied and the 5 cm wide peel force is measured (peel speed 100 mm / min). The peeling force at that time is indicated as follows. 4 g / 5 cm or less: ○ 4 to 10 g / 5 cm: △ 10 g / 5 cm or more: ×

Example 1 An acrylic polymer synthesized from methyl methacrylate, ethyl acrylate, 2-hydroxyethyl methacrylate and N-methylol methacrylamide (Tg = 53 ° C., average particle size: 79 nm, number average molecular weight) : 244000) was prepared as an aqueous liquid A having a solid content concentration of 10%.

A copolymerized polyester having an intrinsic viscosity of 0.54 (Tg = 74 ° C., average) synthesized from terephthalic acid, isophthalic acid, 5-Na sulfoisophthalic acid, ethylene glycol and a propylene oxide adduct of bisphenol A represented by the following structural formula Solid content concentration of 10% (particle size: 51 nm)
Was prepared as aqueous solution B.

[0050]

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[However, n + m = 2 to 10, ph = phenyl group]

On the other hand, a composition comprising 90% by weight of polyethylene terephthalate (intrinsic viscosity: 0.63) and 10% by weight of titanium oxide is melt-extruded on a rotating cooling drum maintained at 20 ° C. to form an unstretched film. After being stretched 3.6 times, 40% by weight of the aqueous liquid A, 30% by weight of the aqueous liquid B, 20% by weight of an aqueous solution (concentration: 10% by weight) of sodium polystyrene sulfonate as an antistatic agent, and poly as a surfactant An aqueous primer coating solution consisting of 10% by weight of an aqueous solution of oxyethylene nonylphenyl ether (concentration: 10% by weight) was applied to both surfaces of the film by a kiss coat method in an amount of 20 g / m ² (wet). Continue in the horizontal direction.
The film was stretched 6 times to obtain a biaxially stretched primer-coated polyester film having a thickness of 188 μm.

The adhesive strength of the magnetic paint, the transferability of the magnetic layer, the adhesive strength of the UV ink, the antistatic property and the blocking resistance of the treated surface of this film are shown in Table 1. 1 together.

Example 2 The same coating liquid composition ratio as in Example 1 except that the antistatic agent used in Example 1 was changed to sodium diphenyl ether disulfonate was 10 g / m 2.
² (wet) was applied to both sides of the film to obtain a biaxially stretched primer-coated polyester film.

Table 1 shows the adhesive strength of the magnetic paint, the transferability of the magnetic layer, the adhesive strength of the UV ink, the antistatic property and the blocking resistance of the treated surface of this film. 1 together.

Comparative Example 1 The acrylic polymer used in Example 1 was an acrylic polymer synthesized from methyl methacrylate, ethyl acrylate, 2-hydroxyethyl methacrylate and N-methylol methacrylamide (Tg = 2).
5 ° C., average particle size: 72 nm, number average molecular weight: 261,000) except that the coating liquid composition ratio was 20 g /
An amount of m ² (wet) was applied to both sides of the film to obtain a biaxially stretched primer-coated polyester film.

The adhesive strength of the magnetic paint, the transferability of the magnetic layer, the adhesive strength of the UV ink, the antistatic property and the blocking resistance of the treated surface of this film are shown in Table 1. 1 together.

Comparative Example 2 The copolyester used in Example 1 was synthesized from terephthalic acid, isophthalic acid, 5-Na sulfoisophthalic acid, 1,4-butanediol and diethylene glycol and had an intrinsic viscosity of 0.52. (Tg = 21 ° C., average particle size: 65 nm) except that the coating liquid composition ratio was exactly 20 g / m ² as in Example 1.
The amount of (wet) was applied to both sides of the film to obtain a biaxially stretched primer-coated polyester film.

The adhesive strength of the magnetic paint, the transferability of the magnetic layer, the adhesive strength of the UV ink, the antistatic property and the blocking resistance of the treated surface of this film are shown in Table 1. 1 together.

Comparative Example 3 The acrylic polymer used in Example 1 was an acrylic polymer synthesized from methyl methacrylate, ethyl acrylate, 2-hydroxyethyl methacrylate and N-methylol methacrylamide (Tg = 5).
5 ° C., average particle size: 158 nm, number average molecular weight: 274000),
Further, a copolymerized polyester (Tg having an intrinsic viscosity of 0.54) synthesized from terephthalic acid, isophthalic acid, 5-Na sulfoisophthalic acid, ethylene glycol and a propylene oxide adduct of bisphenol A is used.
= 75 ° C., average particle size: 146 nm), and a biaxially stretched primer-coated polyester was applied on both surfaces of the film in an amount of 20 g / m ² (wet) in exactly the same coating liquid composition ratio as in Example 1 A film was obtained.

The adhesion of the magnetic paint, the transferability of the magnetic layer, the adhesion of the UV ink, the antistatic property and the blocking resistance of the treated surface of the film are shown in Table 1. 1 together.

Comparative Example 4 The primer coating solution used in Example 1 was prepared by mixing 45% by weight of an aqueous solution A of an acrylic polymer, 45% by weight of an aqueous solution B of a copolymerized polyester, and polyoxyethylene nonylphenyl as a surfactant. A 20 g / m ² (wet) amount was applied to both sides of the film at the same coating liquid composition ratio as in Example 1, except that the primer aqueous coating liquid was composed of 10% by weight of an aqueous solution of ether (concentration: 10% by weight). Thus, a biaxially stretched primer-coated polyester film was obtained.

Table 3 shows the adhesive strength of the magnetic paint, the transferability of the magnetic layer, the adhesive strength of the UV ink, the antistatic property and the anti-blocking property of the treated surface of this film. 1 together.

[Comparative Example 5] In Example 1, the biaxially oriented polyester film obtained without the primer coating had an adhesive force of a magnetic paint, a transferability of a magnetic layer, an adhesive force of a UV ink, an antistatic property, and an antistatic property. Table showing blocking properties and film forming properties of coating films. 1 together.

[0065]

[Table 1]

[0066]

The easily adherent white polyester film according to the present invention has a non-transfer property of a magnetic layer, especially,
Since it has excellent adhesive strength and blocking resistance and good antistatic properties, it is useful for magnetic cards, magnetic disks, printing materials, and the like.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-157790 (JP, A) JP-A-58-124651 (JP, A) JP-A-6-99559 (JP, A) JP-A-3- 17135 (JP, A) JP-A-3-26543 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C08J 7/04

Claims (4)

(57) [Claims] 1. On both sides of a white aromatic polyester film having a thickness of 20 μm or more, (1) 5 to 70% by weight of an aromatic polyester resin having an average particle diameter of 100 nm or less and a secondary transition point of 50 to 120 ° C. (2) the average particle size is 100 nm or less, the secondary transition point is 50 to 120
Using a coating liquid containing a composition consisting of 5 to 70% by weight of an acrylic copolymer having a temperature of 0 ° C. and (3) a substance having a sulfonate group in a molecule of 3 to 50% by weight, the thickness of a dry film is 0.02 to 2 μm.
An easy-adhesion white polyester film coated with an easy-adhesion film. 2. The easily-adhesive white polyester film according to claim 1, wherein the coating liquid is an aqueous coating liquid. 3. The aromatic polyester resin in the aqueous coating solution is dissolved in an aqueous solvent or is finely dispersed with an average particle size of 100 nm or less, and the acrylic copolymer is dissolved in an aqueous solvent or an average particle size. 3. The easily-adhesive white polyester film according to claim 2, which has a diameter of 100 nm or less and is finely dispersed. 4. A laminated film provided with a magnetic layer (magnetic recording layer) and / or a printing ink layer on at least a part of the easily-adhesive coating of the easily-adhesive white polyester film according to claim 1.