JP3210213B2 - Easy adhesion 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 polyester film, and more particularly, to a coating appearance, an easy-adhesion,
The present invention relates to an easily-adhesive polyester film excellent in antistatic properties, particularly to an easily-adhesive white polyester film.

[0002]

2. Description of the Related Art Aromatic polyester films are widely used for magnetic recording materials, printing materials, etc., but a common problem with plastic films is that static electricity is easily generated, and film forming processes, processing processes, and the use of products. However, there are drawbacks that various troubles occur and the adhesion of magnetic paints and printing inks is poor.

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

Conventionally, as a method for improving the antistatic property and adhesiveness, a method of forming a primer layer of a synthetic resin to which an antistatic agent is added in advance on a film surface is known. In this case, an anionic compound or a cationic compound is used as an antistatic agent,
It has been difficult to satisfy both the antistatic property, especially the antistatic property and adhesiveness under low humidity.

In general, a phosphoric acid-based antistatic agent is excellent in antistatic properties, and is also excellent in an application stretching method (in-line coating method) in which an unstretched or uniaxially stretched polyester film is applied as a coating solution, and then the film is stretched and heat-treated. Developed conductivity, antistatic properties, JP-A-6-2550
No. 55, Japanese Patent Publication No. 1-49114, and the like.
However, these methods have poor coatability due to poor wettability of the phosphoric acid-based antistatic agent to the polyester film, and cannot provide a good coated appearance without pretreatment such as corona discharge treatment. Was limited.

[0006]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, by combining a specific surfactant with a phosphate ester-based antistatic agent, a coating solution was prepared. It can be coated well, and has excellent coating appearance, antistatic properties and adhesiveness, and found that an easily adhesive polyester film, particularly a white polyester film, which is extremely useful as a substrate for various applications, is obtained. The present invention has been completed.

[0007]

That is, the present invention relates to an aromatic polyester film having at least one surface having (1) a phosphate ester-based antistatic agent, (2) a surfactant having an HLB of 12 or less, and (3) an acrylic resin. An easy-adhesive polyester film on which an easy-adhesive film is applied using a coating agent containing a composition comprising at least one binder selected from a system copolymer and a polyester copolymer.

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

The aromatic polyester preferably contains a white pigment, for example, 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 composed of heat-resistant polymers such as crosslinked polystyrene resin, crosslinked acrylic resin, urea resin, melamine resin, polyethylene If necessary, other resins such as polypropylene, ethylene-propylene copolymer, and olefin-based ionomers, antioxidants, ultraviolet absorbers, optical brighteners, and the like can be contained.

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 polyester film, particularly the white polyester film, is preferably a biaxially stretched film, and the thickness of the white film is 20 μm or more, preferably 50 to 500 μm, particularly preferably 75 to 300 μm.
m. If the thickness is less than 20 μm, the rigidity of the film as the magnetic card substrate is weak, which is not preferable. On the other hand, if the film is too thick, for example, more than 500 μm, the film-forming properties tend to be poor.

In the present invention, the primer layer (easily adhesive film) provided on at least one side of the polyester film comprises (1) a phosphate ester-based antistatic agent, and (2) HLB.
Is applied to a required surface of the film by applying a coating agent comprising a surfactant of 12 or less and a composition comprising at least one binder selected from (3) an acrylic copolymer and a polyester copolymer, and then drying. It is formed.

In the present invention, the phosphate ester-based antistatic agent (1) constituting the coating agent includes conventionally known compounds. Among them, phosphate ester-based low molecular weight compounds such as phosphorus Acid alkyl ester sodium salt, phosphoric acid alkyl ester potassium salt, aryl phosphate sodium salt, aryl phosphate potassium salt, dialkyl phosphate sodium salt, dialkyl phosphate potassium salt, diaryl phosphate sodium salt, phosphoric acid Potassium diaryl ester, sodium polyalkylene oxide phosphate,
Preferable examples include potassium polyalkylene oxide salts and substituted phosphoric acid partial ester salts. It is preferable to use one selected from these or a combination of two or more.

In the present invention, the surfactant (2) is HLB
Is a surfactant of 12 or less. Here, HLB is Hy
Drophile-Lipophile Balance is an abbreviation for the balance between a lipophilic portion and a hydrophilic portion in a surfactant molecule, and is proposed by Mr. Griffin of Atlas. Its value can be calculated by the following equation (I).

[0015]

(Equation 1)

In the present invention, the phosphate ester antistatic agent (1) constituting the coating agent has a drawback that coating cissing easily occurs on a polyester film due to its high hydrophilicity. When an HLB surfactant is used in combination, the hydrophilicity is reduced and uniform coating becomes possible. HLB
Exceeds 12, hydrophilicity becomes strong and cissing application spots occur.

As the surfactant having an HLB of 12 or less,
For example, polyethylene oxide / polypropylene oxide block copolymer, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene monoalkylate, polyoxyethylene-fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, etc. it can. These may optionally be combined with other surfactants having an HLB of 12 or more.

The acrylic copolymer used as the binder (3) in the present invention comprises acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, sodium acrylate, ammonium acrylate, and the like.
2-hydroxyethyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, sodium methacrylate, ammonium methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, acrylamide, methacrylamide,
N-methylol acrylamide, N-methylol methacrylamide and the like can be exemplified. These monomers can be used in combination with other unsaturated monomers such as styrene, vinyl acetate, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, and divinylbenzene. The acrylic copolymer (3) can also be used as 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.

The acid components forming the polyester copolymer used as the binder (3) in the present invention include terephthalic acid, 2,6-naphthalenedicarboxylic acid,
Examples thereof include isophthalic acid, phthalic acid, phthalic anhydride, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, 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 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 polyester copolymer 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 (ethylene oxide) glycol, poly (Tetramethylene oxide) glycol, and ethylene oxide adducts and propylene oxide adducts of bisphenol A of the following formula

[0021]

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[0022]

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And the like. Two or more of these can be used.

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.
An ethylene oxide adduct or propylene oxide adduct of bisphenol A.

In order to facilitate the aqueous liquefaction of the polyester copolymer, it is possible to copolymerize a small amount of a compound having a sulfonate group or a compound having a carboxylate group, which is more preferable.

Examples of such sulfonic acid group-containing compounds 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 sulfonic acid salt compounds such as 4-K sulfoisophthalic acid, 2-K sulfoisophthalic acid, and Na sulfosuccinic acid, and amine sulfonate compounds.

Examples of the carboxylic acid group-containing compound include trimellitic anhydride, trimellitic acid, pyromellitic anhydride, pyromellitic acid, trimesic acid, cyclobutanetetracarboxylic acid, dimethylolpropionic acid, etc. Metal salts and the like.

The polyester copolymer can also be used as a modified polyester copolymer, for example, a block copolymer or a graft polymer obtained by modifying a polyester copolymer with acryl, polyurethane, silicone, epoxy, phenol resin or the like.

In the present invention, a phosphate ester-based antistatic agent (1), a surfactant (2) having an HLB of 12 or less, and at least one binder selected from acrylic copolymers and polyester copolymers Per the composition consisting of (3), the proportion of the phosphate ester-based antistatic agent (1) is 5 to 40.
%, Preferably 10 to 30% by weight. This ratio is 40
If the amount is more than 5% by weight, the adhesion of the primer layer to the printing ink will be insufficient. On the other hand, if the amount is less than 5% by weight, the antistatic property will be insufficient. The proportion of the surfactant (2) is 1 to 20% by weight, preferably 3 to 15% by weight. If this proportion exceeds 20% by weight, the adhesion of the primer layer to the printing ink will be insufficient, while if it is less than 1% by weight, the wettability of the coating agent to the polyester film will be insufficient.

The primer coating in the present invention is preferably applied as an aqueous coating (using water as a medium), but it is also possible to apply an organic solvent as a solvent.
Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene,
Examples include methanol, ethanol, n-propanol, and isopropanol. These can be used alone or in combination.

In the present invention, a coating agent such as an ultraviolet absorber, a pigment, or the like may be used within a range not to impair the object of the present invention.
Antifoaming agent, coating improver, organic filler, inorganic filler,
Lubricants, anti-blocking agents, melamine, urea,
Other additives such as a guanamine-based, epoxy-based, aziridine-based, blocked isocyanate-based crosslinking agent, and a coupling agent can be blended.

The solid content of the coating composition in the present invention is usually
It is at most 30% by weight, more preferably at most 20% by weight.

In the present invention, a (primer) coating material containing each of the above-mentioned components is applied to at least one surface of the polyester film, and the film is preferably a polyester film before the crystal orientation is completed.

As the polyester film before the completion of the crystal orientation, an unstretched film obtained by melting an aromatic polyester into a film as it is and a non-stretched film are 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.

In particular, a coating agent is applied to the uniaxially stretched film,
It is preferable that the coating film is dried or not dried, and the uniaxially stretched film is stretched in a direction perpendicular to the stretching direction and heat-treated.

The coating can be performed on only one side or both sides depending on the use of the film.

As a method for applying the coating agent 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 brush 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.

In the present invention, the polyester film may be subjected to a corona discharge treatment before the application of the above coating agent. However, the coating agent is not always necessary because the wettability to the polyester film is improved. Absent.

The amount of coating is preferably 0.5 to 50 g, more preferably 3 to 30 g, per m ² of the running film. The thickness of the final dried coating film (coating) is preferably 0.01 to 1 μm,
More preferably, it is 0.02 to 0.6 μm. The thickness of the coating
If the thickness is less than 0.01 μm, sufficient antistatic properties cannot be obtained, and if it exceeds 1 μm, the slipperiness is undesirably reduced.

The magnetic recording layer in the present invention is not particularly limited.
However, the following are typical examples.
Wear. That is, as magnetic powder, for example, γ-Fe_TwoO_Three, C
rO _Two, Co-γ-Fe_TwoO_Three, Fe_ThreeO_Four, BaO ・ 6F
eO_Three, Metal magnetic powder, etc., and as a binder
For vinyl acetate, polyvinylidene chloride, PVC, etc.
Nyl resin, acrylic resin, acrylonitrile / butadier
Rubber-based resins such as copolymers and nitrocellulose
Cellulose, epoxy resin, phenol resin, polyurethane
Using a tan-based resin, etc., if necessary, a dispersant, a lubricant,
Stabilizer, mixed antistatic agent such as carbon, plasticizer, etc.
Things can be mentioned.

The printing ink layer in the present invention is not particularly limited, and may be a conventionally known ultraviolet-curable printing ink, electron beam-curable ink, or heat-sensitive recording ink.

[0042]

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. Appearance of the primer-coated film The appearance of the primer-coated film is visually determined.も の indicates that the coating surface is uniform and has no defect, and X indicates that the coating surface has spots and repelling defects.

2. Adhesive force of magnetic paint The following paint for evaluation was applied to a sample film with a Meyer bar so that the thickness after drying was about 4 μm.
Dry for minutes. After aging at 60 ° C for 24 hours, Scotch tape No. 600 (manufactured by 3M) was adhered to a width of 12.7 mm and a length of 15 cm so that air bubbles did not enter.
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.

[Evaluation paint] 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) 500
A part 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.

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 UV curing device of a medium pressure mercury lamp (80 W / cm, single-lamp type; manufactured by Nippon Battery) to form a UV ink layer having a thickness of 4 μm. A cellophane tape (18 mm width; made by Nichiban) was applied to the UV ink layer to a length of 15 cm, a constant load was applied on the cellophane tape with a 2 kg manual load roll, the film was fixed, and one end of the cellophane tape was fixed at 90 °. The adhesive force is evaluated by peeling in the direction. The adhesive strength is evaluated based on the following five criteria.

5: no ink layer is peeled off 4: less than 3% of ink layer is peeled 3: 3: 10% of ink layer is peeled 2: 10 to 30% of ink layer is peeled 1: 30% 3. The above ink layer peels off. Antistatic properties

The antistatic property was evaluated based on the surface resistivity of the sample film. As the surface resistivity, a resistivity measuring device manufactured by Takeda Riken Co., Ltd. was used.
% And 45%, the surface specific resistance (Ω / □) after one minute at an applied voltage of 500 V is measured. 1 × 10 ¹¹ Ω / □ or less is preferable.

Example 1 Solid Concentration of Acrylic Copolymer (Number Average Molecular Weight: 253000) Prepared from Methyl Methacrylate, Ethyl Acrylate, 2-Hydroxyethyl Methacrylate and N-Methylol Methacrylamide
% Of an aqueous dispersion was prepared and used as an aqueous liquid A.

On the other hand, a composition comprising 90% by weight of a polyester (intrinsic viscosity: 0.63) made of terephthalic acid and ethylene glycol and 10% by weight of titanium oxide is melt-extruded on a rotary cooling drum maintained at 20 ° C. Then, after stretching 3.6 times in the machine axis direction, 70% by weight of the aqueous liquid A, 20% by weight of an aqueous solution of dioctyl phosphate sodium salt as an antistatic agent (concentration: 10% by weight), and a surfactant Aqueous solution of polyoxyethylene nonyl ether (HLB = 11.5) (concentration: 10% by weight)
4 g / m ² (w
et) was applied to both sides of the film by a kiss coat method. Subsequently, the film was stretched 3.9 times in the transverse direction to obtain a primer-coated biaxially stretched polyester film having a thickness of 188 μm.

Table 1 shows the coating appearance of the treated surface of the film, the adhesion of the magnetic paint, the adhesion of the UV ink and the antistatic property.
Are shown together.

Example 2 A copolymerized polyester (Tg) having an intrinsic viscosity of 0.53 made 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 (= 76 ° C.) and an aqueous dispersion having a solid concentration of 10% was prepared as an aqueous liquid B.

[0053]

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The aqueous liquid A used in Example 1 was replaced with the aqueous liquid B
Except that the composition was changed to 4 in the same coating composition ratio as in Example 1.
An amount of g / m ² (wet) was applied to both sides of the film to obtain a primer-coated biaxially oriented polyester film.

Table 1 shows the coating appearance of the treated surface of the film, the adhesion of the magnetic paint, the adhesion of the UV ink and the antistatic property.
Are shown together.

Example 3 The coating composition used in Example 1 was prepared by adding 40% by weight of aqueous liquid A, 30% by weight of aqueous liquid B, and an aqueous solution of dipentyl phosphate potassium salt as an antistatic agent (concentration: 10% by weight). ) And 20% by weight of a surfactant, polyoxyethylene nonylphenyl ether (HLB = 1)
0.9) of 10% by weight aqueous solution (concentration 10% by weight), except that the amount of 4 g / m ² (wet) was applied at the same coating composition ratio as in Example 1 except that the coating composition was changed to 10% by weight. To obtain a primer-coated biaxially stretched polyester film.

Table 1 shows the coating appearance of the treated surface of the film, the adhesion of the magnetic paint, the adhesion of the UV ink and the antistatic property.
Are shown together.

Comparative Example 1 The surfactant used in Example 1 was polyoxyethylene nonyl phenyl ether (HLB).
= 14.0), except that the amount of 4 g / m ² (wet) was applied to both surfaces of the film at the same coating composition ratio as in Example 1 to obtain a primer-coated biaxially stretched polyester film.

Table 1 shows the coating appearance of the treated surface of the film, the adhesion of the magnetic paint, the adhesion of the UV ink and the antistatic property.
Are shown together.

Comparative Example 2 The coating composition used in Example 1 was composed of 50% by weight of an aqueous liquid A and an aqueous solution (concentration: 10% by weight) of potassium dipentyl phosphate as an antistatic agent.
Coating exactly the same as in Example 1 except that the coating was changed to a coating consisting of 0% by weight and 10% by weight of an aqueous solution (concentration: 10% by weight) of polyoxyethylene nonylphenyl ether (HLB = 10.9) as a surfactant. 4g / m ² (we
The amount of t) was applied to both sides of the film to obtain a primer-coated biaxially oriented polyester film.

Table 1 shows the coating appearance of the treated surface of the film, the adhesion of the magnetic paint, the adhesion of the UV ink and the antistatic property.
Are shown together.

Comparative Example 3 Example 1 was repeated except that the antistatic agent used in Example 1 was changed to sodium dodecyl sulfonate.
An amount of 4 g / m ² (wet) was applied to both sides of the film at the same coating composition ratio as in Example 1 to obtain a primer-coated biaxially stretched polyester film.

Table 1 shows the coating appearance of the treated surface of the film, the adhesiveness of the magnetic paint, the adhesive strength of the UV ink, and the antistatic property.
Are shown together.

Comparative Example 4 The adhesiveness of the magnetic paint, the adhesive strength of the UV ink, and the antistatic property on the surface of the biaxially stretched polyester film obtained in Example 1 without the primer coating are shown in Table 1. .

[0065]

[Table 1]

[0066]

The easily adhesive polyester film according to the present invention has a particularly excellent coating appearance, adhesive strength and antistatic property as compared with conventional ones. For example, a magnetic card, a magnetic disk, a printing material, a graphic material, Useful for photosensitive materials and the like.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 27/00-27/42 C08J 7/04

Claims (6)

(57) [Claims] 1. An aromatic polyester film having on at least one surface thereof (1) a phosphate ester-based antistatic agent, (2) HL
An antistatic easy-to-adhesive coating is applied using a coating containing a surfactant having a B of 12 or less and a composition comprising at least one binder selected from (3) an acrylic copolymer and a polyester copolymer. Easy adhesion polyester film. 2. The easily adhesive polyester film according to claim 1, wherein the aromatic polyester film is a white film containing a white pigment and having a thickness of 20 μm or more. 3. The easily adhesive polyester film according to claim 1, wherein the coating agent is an aqueous coating agent. 4. A phosphate ester-based antistatic agent,
The proportion of (2) surfactant and (3) binder is 5 to 40% by weight, 1 to 20% by weight and 94 to
The easily adhesive polyester film according to claim 1, which is 40% by weight. 5. The easily-adhesive polyester film according to claim 1, wherein the thickness of the easily-adhesive film is from 01 to 1 μm. 6. A laminated film provided with a magnetic recording layer and / or a printing ink layer on at least a part of the easily adhesive coating of the easily adhesive polyester film according to claim 2.