JP3502477B2 - 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 specifically, a coating appearance, an easily adhesive property,
The present invention relates to an easily-adhesive white polyester film having excellent antistatic properties.

[0002]

2. Description of the Related Art White films made of aromatic polyester containing a white pigment such as titanium oxide are widely used in magnetic recording materials, printing materials, etc. There are drawbacks in that various troubles are likely to occur during the film forming process, the processing process, the use of the product, and the like, and the adhesiveness of the magnetic paint and the printing ink is poor.

Thick white polyester films are used for magnetic cards such as telephone cards and prepaid cards. The manufacturing process, processing process, antistatic property of the final product, UV ink and magnetic paint are used. Adhesion is difficult, and application of a primer has been proposed.

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

Generally, a cationic compound such as a quaternary ammonium salt is excellent in antistatic property under low humidity but inferior in thermal stability, and is applied as a coating agent to an unstretched or uniaxially stretched polyester film and then stretched. In the coating and stretching method (in-line coating method) in which heat treatment is performed, the performance is often deactivated. Among them, polycationic polymers having a plurality of quaternized aminocationic groups in the main chain exhibit excellent conductivity and antistatic property even in the coating and stretching method. -288217, etc. However, with these methods, the wettability of the cationic polymer to the polyester film is poor, the coatability is poor, and a good coating appearance cannot be obtained, and its application is limited.

[0006]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of the above problems, the present inventors have combined a specific surfactant with a polycationic polymer having a plurality of quaternized aminocationic groups in its main chain. By that, it can be applied well as a coating liquid, and has an excellent coating appearance and antistatic property and adhesiveness, and found that an easily adhesive white polyester film extremely useful as a substrate for various applications can be obtained,
The present invention has been completed.

[0007]

That is, the present invention provides a polycationic polymer having a plurality of quaternized aminocationic groups in the main chain on at least one side of an aromatic polyester film containing a white pigment and having a thickness of 20 μm or more. , (2) HL
An easily-adhesive white polyester film in which an easily-adhesive coating is applied using a coating agent containing a composition having a B of 12 or less and (3) an acrylic copolymer.

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

And, 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, and talc, organic fillers such as crosslinked polystyrene resin, crosslinked acrylic resin, urea resin, and melamine resin,
Other resins such as polyethylene, polypropylene, ethylene-propylene copolymer, olefinic ionomers, antioxidants, ultraviolet absorbers, optical brighteners, etc. may be contained as required.

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 glossiness thereof can be arbitrarily selected.

In the present invention, the white polyester film is preferably a biaxially stretched film, and its thickness is
20 μm or more, preferably 50 to 500 μm, particularly preferably 7
It is 5 to 300 μm. If this thickness is less than 20 μm, the film has a soft texture and is not suitable. On the other hand, the film is too thick,
For example, if it exceeds 500 μm, the film-forming property tends to be poor.

In the present invention, the primer layer (easy-adhesive coating) provided on at least one side of the white polyester film is (1) a polycationic polymer having a plurality of quaternized aminocationic groups in the main chain, and (2) HLB of 12 It is formed by applying a coating composition containing the following surfactant and a composition comprising (3) an acrylic copolymer on a required surface of the film and drying it.

In the present invention, the main chain constituting the coating agent is 4
Examples of the polycationic polymer (1) having a plurality of graded aminocationic groups include polymers having the following units.

[0014]

[Chemical 1]

In the above formula, R₁~ R_FourEach has a single valence
Functional groups such as alkyl groups, cycloalkyl groups, aryl
Group, aralkyl group, monovalent group containing hetero atom, etc.
R _Five~ R₆Are each a divalent organic group such as alkylene
Group, cycloalkylene group, arylene group, aralkylene
Group, a divalent group containing a hetero atom, and the like.
JP-A-3-255139, JP-A-4-288217, etc.
Examples of the compounds include those described in, but not limited to
It is not something that will be done.

In the present invention, the surfactant (2) includes
At least one surfactant selected from surfactants having an HLB of 12 or less is preferable. HL in the present invention
B is an abbreviation of Hydropile-Lipophile Balance, which is a numerical representation of the balance of lipophilic and hydrophilic moieties in the molecule of the surfactant, and was proposed by Griffin of Atlas. The value can be calculated by the following formula (I).

[0017]

## EQU1 ## HLB = 20 (1-M _O / M) (where M _O is the molecular weight of the hydrophobic group and M is the molecular weight of the surfactant)

In the present invention, 4 is contained in the main chain which constitutes the coating material.
The polycationic polymer (1) having a plurality of quaternized aminocationic groups has a drawback that coating repellency is likely to occur on a polyester film due to its high hydrophilicity, but when the above-mentioned low HLB surfactant is used in combination, Hydrophilicity is relaxed and uniform application becomes possible. When HLB exceeds 12, hydrophilicity becomes strong and cissing application spots occur.

As the surfactant having an HLB of 12 or less,
Examples include polyethylene oxide / polypropylene oxide block copolymers, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene monoalkylates, polyoxyethylene-fatty acid esters, sorbitan fatty acid esters, glycerin fatty acid esters. You can
It is also possible to combine other surfactants having an HLB of 12 or more.

In the present invention, the acrylic copolymer (3) is composed of acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, sodium acrylate, ammonium acrylate, 2-hydroxyethyl acrylate, methacrylic acid. Examples include acids, 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. be able to. These monomers are, for example, styrene,
Vinyl acetate, acrylonitrile, methacrylonitrile,
It can also be used in combination with other unsaturated monomers such as vinyl chloride, vinylidene chloride and divinylbenzene. As the acrylic copolymer (3), a modified acrylic copolymer, for example, a block polymer or graft polymer obtained by modifying an acrylic copolymer with polyester, polyurethane, silicone, epoxy, phenol resin or the like can be used.

The coating material in the present invention is preferably an aqueous coating material (using a water solvent), but it is also possible to apply it using 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, methanol, ethanol, n.
-Propanol, isopropanol and the like can be exemplified. These may be used alone or in combination of two or more.

In the present invention, for example, an ultraviolet absorber, a pigment, an antifoaming agent, a coatability improving agent, an organic filler, an inorganic filler, a lubricant, an antiblocking agent, and melamine within a range that does not impair the object of the present invention. Other additives such as a crosslinking agent such as a system, a urea system, a guanamine system, an epoxy system, an aziridine system, a blocked isocyanate system, and a coupling agent can be mixed with the coating agent.

The solid content concentration of the coating material in the present invention is usually
It is 30% by weight or less, more preferably 20% by weight or less.

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

As the white polyester film before completion of the crystal orientation, an unstretched film obtained by heat-melting the polyester to form a film as it is, orienting the unstretched film in either the longitudinal direction or the transverse direction. Uniaxially stretched film, those which have been stretched and oriented at a low ratio in the longitudinal and transverse directions (the biaxially stretched film before being finally reoriented in the longitudinal or transverse direction to complete the oriented crystallization), etc. It can be illustrated.

When the coating material is applied to the white polyester film before the crystal orientation is completed, it is preferable to stretch after the application to complete the crystal orientation. For the stretching treatment, conventionally known methods, conditions and the like can be adopted.

As a method of 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 micro gravure coating method, a reverse coating method, a roll brushing method, a spray coating method, an air knife coating method, an impregnation method and a curtain coating method may be applied alone or in combination. The aqueous coating composition may contain a small amount of an organic solvent for the purpose of assisting the stability of the coating composition or the coating property of the coating composition.

The coating amount is preferably 0.5 to 50 g, more preferably 5 to 30 g per 1 m ² of the running film. The thickness of the final dry coating film (coating) is required to be 0.01 to 1 μm, preferably 0.02 to 0.6 μm. Coating thickness is 0.0
If it is less than 1 μm, sufficient antistatic property cannot be obtained.
On the other hand, when it exceeds 1 μm, the slipperiness is deteriorated, which is not preferable.

The coating can be carried out on one side only or on both sides depending on the intended use of the film. After coating, it is dried to form a uniform coating film.

The magnetic recording layer in the present invention is not particularly limited, but typical examples thereof include the following. That is, as magnetic powder, γ-Fe ₂ O ₃ , CrO
₂ , Co-γ-Fe ₂ O ₃ , Fe ₃ O ₄ , BaO · 6Fe
O ₃ , metal magnetic powder, and as a binder, vinyl acetate resin, polyvinylidene chloride, vinyl resin such as PVC, acrylic resin, rubber resin such as acrylonitrile / butadiene copolymer, fibrin such as nitrocellulose, epoxy Examples include a mixture of a system resin, a phenol resin, a polyurethane resin, and a dispersant, a lubricant, a stabilizer, an antistatic agent such as carbon, and a plasticizer which are added as necessary.

The printing ink layer in the present invention is not particularly limited, but conventionally known UV-curable printing ink, electron beam-curable ink, heat-sensitive recording ink and the like can be used.

[0032]

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

1. Stability of coating agent A coating agent having a solid content concentration of 10% by weight was prepared, and 30 ml of this coating agent was dispensed into a glass test tube and allowed to stand still at room temperature for 24 hours, after which the bottom agglomerates were visually determined. A sample having no change in its properties is marked with ◯, and a precipitate or gelled sample is marked with x.

2. Appearance of application of primer-coated film The appearance of application of the primer-coated film is visually determined. The case where the coated surface is uniform and has no defects is marked with ◯, and the case where there are spots or cissing defects is marked with x.

3. Adhesive strength of magnetic paint The following evaluation paint was applied to a sample film with a Meyer bar so that the thickness after drying would be about 4 μm, and the film was dried at 100 ° C for 3 days.
Dry for minutes. After that, it was aged at 60 ° C for 24 hours, and then Scotch tape No. 600 (3M) with a width of 12.7 mm and a length of 15 cm was adhered to it so that no bubbles could enter it, and the top of this was JI.
Using a manual load roll described in SC2701 (1975), the film is leveled and brought into close contact and cut into a tape width. The strength when 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 S-REC A (manufactured by Sekisui Chemical Co., Ltd.), dispersant Recion P (manufactured by Riken Vitamin) in terms of solid content ) 1 part by weight and magnetic agent CTX-860 (manufactured by Toda Kagaku) 50
0 part by weight is dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to prepare a 40% solution, which is dispersed by a sand grinder for 2 hours. Then cross-linking agent Coronate L
Add 25 parts by weight (as solid content) and stir well to obtain a magnetic paint.

4. Adhesive strength of UV ink To the sample film, UV curable printing ink (Flash Dry FD Carton P Hongro made by Toyo Ink) is RI
After printing with a tester (manufactured by Akira Seisakusho Co., Ltd.), a UV ink layer having a thickness of 4 μm is formed by curing with a medium pressure mercury lamp (80 W / cm, one lamp type; manufactured by Nippon Battery) UV curing device. Cellophane tape (18 mm width; made by Nichiban) was pasted on this UV ink layer to a length of 15 cm, and a fixed load was applied with a 2 kg manual load roll, and the film was fixed and one end of the cellophane tape was 90 °. The adhesive strength is evaluated by peeling in the direction. The adhesive strength was evaluated according to the following 5 grades. 5: The ink layer does not peel at all 4: Less than 3% of the ink layer peels off 3: 3 to 10% of the ink layer peels off 2:10 to 30% of the ink layer peels off 1: 30% or more of the ink Layers peel

5. The surface resistivity of the antistatic sample film is manufactured by Takeda Riken.
Using a specific resistance measuring instrument, measuring temperature 23 ℃, measuring humidity 65%
And the 45% condition, the surface specific resistance value (Ω / □) after 1 minute at an applied voltage of 500 V is measured and displayed. 1 x 10 ¹¹ Ω /
□ The following are preferable.

Example 1 Polyester made from terephthalic acid and ethylene glycol (intrinsic viscosity 0.62)
A composition consisting of 90% by weight and 10% by weight of titanium oxide was melt extruded on a rotary cooling drum maintained at 20 ° C. to obtain an unstretched film, which was then stretched 3.6 times in the machine axis direction, and then methyl methacrylate, Acrylic polymer consisting of ethyl acrylate and N-methylol acrylamide (number average molecular weight:
70% by weight of an aqueous dispersion having a solid content concentration of 329000) and a polycationic polymer having a plurality of quaternized aminocationic groups in the main chain of the following structure which is an antistatic agent (number average molecular weight:
6200) 20% by weight aqueous solution (concentration 10% by weight) and surfactant polyoxyethylene nonyl ether (HLB)
= 11.5) aqueous solution (concentration 10% by weight) 10% by weight was applied to both surfaces of the film by the kiss coating method in an amount of 10 g / m ² (wet). Subsequently, the film was stretched 3.9 times in the transverse direction to obtain a primer-coated biaxially stretched polyethylene terephthalate film having a thickness of 188 μm.

[0040]

[Chemical 2]

Table 1 shows the adhesion of the magnetic coating on the treated surface of this film, the adhesion of the UV ink, the antistatic property and the stability of the coating material used.

Example 2 The surfactant used in Example 1 was changed to polyoxyethylene nonylphenyl ether (HLB).
= 10.9) except that the coating composition ratio was exactly the same as in Example 1 except that 10 g / m ² (wet) was applied to both sides of the film to obtain a primer-coated biaxially oriented polyethylene terephthalate film. .

Table 1 shows the adhesiveness of the magnetic paint, the adhesive strength of the UV ink, the antistatic property and the stability of the coating material used on the treated surface of this film.

[Comparative Example 1] The surfactant used in Example 1 was polyoxyethylene nonylphenyl ether (HLB).
= 14.0) except that the coating composition ratio was exactly the same as in Example 1 except that 10 g / m ² (wet) was applied to both sides of the film to obtain a primer-coated biaxially oriented polyethylene terephthalate film. .

Table 1 shows the adhesion of the magnetic paint, the adhesion of the UV ink, the antistatic property and the stability of the coating material used on the treated surface of this film.

Comparative Example 2 The stability of the coating composition was poor when the coating composition ratio was exactly the same as in Example 1 except that the surfactant used in Example 1 was changed to sodium dodecyl benzene sulfonate. It was difficult to apply it to the film. The stability of the coating composition is summarized in Table 1.

Comparative Example 3 The acrylic polymer used in Example 1 was changed to a copolyester (Tg = 15 ° C.) having an intrinsic viscosity of 0.56 made from terephthalic acid, isophthalic acid, 5-Nasulfoisophthalic acid and diethylene glycol. When the coating composition ratio was exactly the same as in Example 1 except that the coating composition was changed, it was difficult to apply the composition to the film due to poor stability of the coating composition. The stability of the coating composition is summarized in Table 1.

[Comparative Example 4] The coating composition ratio was exactly the same as in Example 1 except that the antistatic agent used in Example 1 was changed to sodium dodecyl sulfonate, and the coating composition ratio was 10 g / m ² (wet).
Was applied to both sides of the film to obtain a primer-coated biaxially stretched polyethylene terephthalate film.

Table 1 shows the adhesion of the magnetic coating, the adhesion of the UV ink, the antistatic property, and the stability of the coating used on the treated surface of this film.

[Comparative Example 5] Example 5 was repeated except that the antistatic agent used in Example 1 was changed to a copolymer consisting of methyl methacrylate, ethyl acrylate, 2-hydroxyethyl methacrylate and dimethylaminoethyl methacrylate quaternary compound. With the same coating composition ratio as in Example 1, 10 g / m ² (w
Et) was applied to both sides of the film to obtain a primer-coated biaxially oriented polyethylene terephthalate film.

Table 1 shows the adhesion of the magnetic coating, the adhesion of the UV ink, the antistatic property and the stability of the coating used on the treated surface of this film.

[Comparative Example 6] Table 1 shows the adhesion of the magnetic coating, the adhesion of the UV ink, and the antistatic property on the surface of the biaxially stretched polyethylene terephthalate film obtained in Example 1 without the primer coating. Show.

[0053]

[Table 1]

[0054]

EFFECTS OF THE INVENTION The easily adhesive white polyester film according to the present invention is particularly excellent in the appearance of the coating film as compared with the conventional one, and is also excellent in the adhesive force and the antistatic property. It is useful for disks, printing materials, graphic materials, photosensitive materials and the like.

Continuation of front page (56) Reference JP-A-4-288217 (JP, A) JP-A-3-255139 (JP, A) JP-A-1-232610 (JP, A) JP-A-7-40521 (JP , A) JP 62-292433 (JP, A) JP 2-73833 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 C08J 7/04

Claims (3)

(57) [Claims] 1. An aromatic polyester film containing a white pigment and having a thickness of 20 μm or more, (1) a polycationic polymer having a plurality of quaternized aminocationic groups in the main chain, and (2) an HLB of 12 or less. Surfactant and
(3) An easily-adhesive white polyester film having an easily-adhesive coating applied by using a coating agent containing a composition comprising an acrylic copolymer. 2. The easily adhesive white polyester film according to claim 1, wherein the coating agent is an aqueous coating agent. 3. A laminated film in which a magnetic recording layer and / or a printing ink layer is provided on at least a part of the easily adhesive coating of the easily adhesive white polyester film according to claim 1.