KR100244761B1 - Polyester film and magnetic tape prepared therefrom - Google Patents

Abstract

The present invention polymerizes a dicarboxylic acid component and a glycol component to obtain a polyester resin, melt-extrudes the resin to obtain an unstretched sheet, and at least 60% of the main repeating units produced by biaxially stretching the sheet are ethylene. A biaxially oriented polyester film made of terephthalate or ethylene naphthalate, wherein the film has an average particle diameter of 0.01 to 2.0 µm and 0.01 to 2.0 weight based on 100 parts by weight of the dicarboxylic acid component based on particles inactive to the polyester. And a dispersion coating solution of a polyester-based polyurethane resin on at least one side of the polyester unstretched sheet or at least one uniaxially stretched polyester film in an amount of 0.01 to 0.5 g / m 2 based on solid content. Characterized by a biaxially oriented polyester film and a magnetic tape made therefrom In one embodiment, the film has a low surface roughness and high adhesion to a magnetic material, and thus can be used to economically prepare excellent magnetic tape.

Description

Polyester film and magnetic tape made therefrom

The present invention is very excellent in adhesion to the magnetic material to be applied for the manufacture of magnetic tape to reduce the content of binder resin (Binder resin) used to increase the durability and adhesive strength of the magnetic material or to be replaced by an inexpensive product to reduce the cost The present invention relates to a functional polyester film that can greatly contribute and a magnetic tape coated with a magnetic material on the functional polyester film.

Among the polyesters, polyethylene terephthalate is particularly chemically and physically stable, has high mechanical strength, and is excellent in heat resistance, durability, weather resistance, electrical insulation, and chemical resistance, so as to be used in medical, industrial, magnetic recording media, capacitors, packaging, and photography. It is used in a wide range of fields for various molded articles, as well as for films and labels.

Conventionally, bonding resins such as acrylic resins and polyurethane resins were added to a coating liquid containing a magnetic material as a main component to improve adhesion to the magnetic material. However, this has a disadvantage in that the electronic properties of the final magnetic tape are inferior due to impaired dispersibility of the magnetic material. there was.

An object of the present invention is to provide a functional polyester film having excellent adhesion to a magnetic body and a magnetic tape prepared therefrom.

In order to achieve the above object, in the present invention, a main repeating unit is prepared by polymerizing a dicarboxylic acid component and a glycol component to obtain a polyester resin, melt extruding the resin to obtain an unstretched sheet, and biaxially stretching the sheet. In the biaxially oriented polyester film of 60% or more of ethylene terephthalate or ethylene naphthalate, the film is 100 parts by weight of the dicarboxylic acid component of the average particle diameter of 0.01 to 2.0㎛ 0.01 to 2.0 parts by weight, based on at least one side of the polyester unstretched sheet or at least uniaxially stretched polyester film, a dicarboxylic acid component, a glycol component, the following general formula (I) and the following general formula ( Solid dispersion of the dispersion coating liquid of polyester-type polyurethane resin manufactured by copolymerizing the component of II) It provides a biaxially oriented polyester film characterized in that the coating in an amount of 0.01 to 0.5g / ㎡ based on:

In the above formula,

R is a C _1-10 aliphatic hydrocarbon group, R ¹ , R ² and R ³ are independently of each other a C _1-5 alkyl group, n and m are each independently an integer from 1 to 5.

In order to achieve another object of the present invention to provide a magnetic tape prepared by applying a dispersion of the magnetic material on the surface coated with the polyester-based polyurethane of the functional polyester film and dried.

Hereinafter, the present invention will be described in detail.

The polyester used in the present invention uses an intrinsic viscosity of 0.4 to 0.9 g / dl measured at a concentration of 0.3 g per 25 ml of orthochlorophenol at 35 ° C. If the intrinsic viscosity is less than 0.4 g / dl, breakage occurs frequently during stretching, which leads to a decrease in productivity as well as to a decrease in physical properties such as mechanical strength in the final film. When the viscosity is higher than 0.9 g / dl, the melt viscosity increases significantly. As the extrudeability is lowered, productivity in the post process is lowered.

In this invention, polyester polycondenses the acid component which has aromatic dicarboxylic acid as a main component, and the glycol component which has alkylene glycol as a main component. Specific examples of the aromatic dicarboxylic acid include dimethyl terephthalate, terephthalic acid and isophthalic acid. Naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, anthracenedicarboxylic acid, α, β-bis (2 -Chlorophenoxyethane-4,4'-dicarboxylic acid, and the like, of which dimethyl terephthalate, terephthalic acid and naphthalenedicarboxylic acid are particularly preferred, as alkylene glycol, ethylene glycol, trimethylene glycol, tetramethylene Glycol, pentamethylene glycol, hexamethylene glycol, hexylene glycol, and the like can be used, and among these, ethylene glycol is particularly preferable.

The polyester in the present invention is a homopolyester of at least 60% by weight of polyethylene terephthalate or polyethylenenaphthalate, and copolymerizable within 40% by weight. Specific examples of the copolymer component include dicarboxylic acid components and trimellis such as diethylene glycol, propylene glycol, neopentyl glycol, polyethylene glycol, p-xylene glycol, 1,4-cyclohexanedimethanol, and 5-sodium sulfolezocin Polycarboxylic acid components, such as a triacid and a pyromellitic acid, etc. are mentioned.

In addition, the polyester film of the present invention contains inert particles in an amount of 0.01 to 2.0 parts by weight based on 100 parts by weight of the dicarboxylic acid component, and when the content of the particles is less than 0.01 part by weight, the number of irregularities formed on the surface of the film If it is small, this activity becomes poor, and when it contains 2.0 weight part or more, the film surface will roughen and it is unpreferable.

The average particle diameter of the particles is 0.01 to 2.0 mu m, preferably 0.1 to 1.5 mu m. If the average particle diameter of the particles is less than 0.01 μm, the size of the irregularities formed on the surface of the film is small, so that the activity is poor. If the average particle diameter of the particles is larger than 2.0 μm, the surface of the polyester film is roughened and the electronic properties are poor. Become.

The particles inert to the polyester may be any of known inorganic particles such as calcium carbonate, dolomite, glass spare, glass fiber, active, kaolin, mica, silica, barium sulfate, aluminum silicate, alumina, titanium dioxide, and the like. . In addition, organic particles such as copolymers with compounds having one aliphatic unsaturated bond in the molecule and fine particles of thermosetting phenol resins, thermosetting epoxy resins, thermosetting urea resins, benzoguanamine resins and fluorine-based resins may also be used. There is no restriction | limiting in particular in a kind, You may use individually by 1 type, and may mix and use 2 or more types.

The main components of the dispersion coating liquid used in the present invention are water-dispersible polyester-based polyurethane resins, which include a dicarboxylic acid component, a glycol component, a carboxylic acid glycol component of the general formula (I), and a diisocyanate of the general formula (II). It is prepared by copolymerizing the components.

Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 1,4-naphthalene dicarboxylic acid, 2,5-dimethyl terephthalic acid, and dimethylisophthalic acid, and 1,3-cyclopentane dicarboxylic acid. Alicyclic dicarboxylic acids such as acids, 1,3-cyclohexane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid, and the like, and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, and the like. Of these, aromatic dicarboxylic acids are particularly preferred.

C _2-8 aliphatic glycols and C _6-12 alicyclic glycols are useful as glycol components, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neo Pentyl glycol, 1,6-hexanediol, 1,2-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, 1,4-cyclohexane dimethanol, p-xylene glycol, diethylene glycol, triethylene glycol Etc. can be used.

Compounds of formula (I) may be prepared by methods known in the literature or may be purchased commercially.

5-Isocyanato-1-isocyanatomethyl-1,3-3-trialkyl cyclohexane of the general formula (II) can be prepared by a known method or commercially available. It is preferable that R <^1> , R <^2> and R <^3> is respectively a methyl group, an ethyl group, a propyl group, or a butyl group among the compound of general formula (II), and it is more preferable that R <^1> , R <^2> and R <^3> are all methyl groups especially. .

The repeating unit of the polyester-based polyurethane resin used in the present invention consists of a polyester-based component and a polyurethane component. The polyester-based component is formed from the dicarboxylic acid component and the glycol component, and the polyurethane component is formed from the carboxylic acid glycol component of the general formula (I) and the diisocyanate component of the general formula (II).

The polyester-based polyurethane resin can be manufactured by copolymerizing the said dicarboxylic acid component, the glycol component, the compound of general formula (I), and the diisocyanate component of general formula (II) by a conventional polymerization method.

In addition, the polyester component and the polyurethane component is prepared to have a weight ratio of 10:90 to 90:10, preferably 80:20 to 70:30.

1 to 10% by weight of the polyester-based polyurethane resin prepared as described above and 0.01 to 0.5% by weight of the surfactant as an additive is dispersed in a polar solvent such as water to prepare an aqueous dispersion.

The aqueous dispersion according to the present invention does not deteriorate the adhesion between the adhesive layer and the base film with other additives known in the art, for example, antistatic agents, wetting agents, pH adjusting agents, antioxidants, dyes, pigments, slip agents, and the like. It can be contained in an effective amount within a range.

The manufacturing method of the polyester film of this invention is not specifically limited except adding an inert particle and apply | coating a polyurethane resin, It can manufacture by any conventional method known in the art. Preferably, the polyester resin is usually melt-extruded and electrostatically applied on a cooling roll at 20 to 30 ° C. to form a sheet, and then the unstretched sheet is 2 to 5 times in a longitudinal direction at 70 to 100 ° C., preferably Is stretched 3 to 4 times, stretched 2 to 5 times, preferably 3 to 4 times in the transverse direction at 70 to 100 ° C, and then biaxially stretched at 100 to 260 ° C, preferably 220 to 240 ° C. The sheet is heat-set to produce a biaxially stretched polyester film.

The dispersion coating solution containing the water-dispersible polyester-based polyurethane resin used in the present invention as a main component may be applied to at least one side of the polyester unstretched sheet or to at least one side of the at least uniaxially stretched sheet. The thickness of the coating layer is 0.001 to 1 µm, and the resin solid content in the coating layer is 0.01 to 0.5 g / m ² . Subsequently, the said application layer is dried and the polyester film of this invention can be manufactured through a conventional process.

In the present invention, the method of applying the aqueous dispersion may be used a conventional method such as a method using a roll such as gravure roll, reverse gravure roll, a method using a bar such as Mayer bar, a method using an air knife method, and the like.

When a magnetic tape is prepared by applying a coating liquid containing a known magnetic substance as a main component to a surface coated with a polyester-based polyurethane resin of the functional polyester film of the present invention, a magnetic tape having excellent adhesion to the magnetic layer is obtained. You can get it.

The magnetic body coating liquid used in the present invention includes a magnetic body, a binder, a curing agent and other additives.

As the magnetic material, iron oxides such as γ-Fe ₂ O ₃ , Co-γ-Fe ₂ O ₃ , α-Fe, and iron magnetic powder are used.

The present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited only to the following examples. Various performance evaluations of the resins, films, and processes prepared in Examples and Comparative Examples of the present invention were carried out by the following method:

(1) average particle diameter

After capturing 50 sites of particles using a scanning electron microscope (magnification x50 only), the particle size of each site was measured by an image analyzer, and the average particle diameter was obtained by arithmetic average.

(2) Surface roughness measurement (Ra)

The surface roughness of the polyester film sample was measured using a three-dimensional non-contact surface roughness measuring instrument (product of WYKO).

(3) adhesiveness with magnetic layer

A non-stretched polyethylene sheet or polypropylene sheet having a thickness of 60 µm is laminated on the surface of the polyester film to which the magnetic layer is applied by a conventional dry lamination method, and then left to stand at 50 ° C for 24 hours for aging. After the treatment is completed, the polyethylene or polypropylene laminate is cut into 15 mm pieces to peel off the polyester film with the magnetic layer and a portion of one end of the polyethylene or polypropylene sheet laminated thereon, The peel force between layers was measured.

Example 1

1) Preparation of polyester polyurethane resin dispersion

Copolymerization using dimethyl terephthalic acid and isophthalic acid as the dicarboxylic acid component, ethylene glycol and diethylene glycol as the glycol component, 5-isocyanato-1-isocyanatomethyl-1,3,3-trimethyl cyclohexane To prepare a polyurethane component, and then add a compound of the formula (I) to it, and then copolymerize it by a conventional copolymerization method, wherein the water-dispersible polyester having a polyester component to polyurethane component ratio of about 25:75 weight ratio System-based polyurethane resin was prepared.

The aqueous dispersion was prepared such that the concentration of the obtained polyester-based polyurethane resin was 1% by weight (based on solids content) and the concentration of the surfactant was 0.05% by weight.

2) polyester film production

100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol and 0.05 parts by weight of calcium acetate were placed in a reactor, and a transesterification reaction was carried out. After 4 hours, 0.3 parts by weight of calcium carbonate particles, 0.06 parts by weight of trimethyl phosphate, and 0.04 parts by weight of antimony trioxide were added to the system in which the transesterification reaction was substantially completed, followed by polymerization for 5 hours by a conventional method. A resin was obtained.

Subsequently, the polyester resin was melt extruded, electrostatically applied on a cooling roll at 20 to 30 ° C. to be molded into sheets, and then the unstretched sheet was stretched 3 to 4 times in the longitudinal direction at 70 to 100 ° C.

On one side of the uniaxially stretched sheet, the aqueous dispersion was applied so that the thickness of the coating layer before drying was 5 to 6 mu m. Subsequently, the coating liquid applied at the same time was dried while stretching the sheet 3 to 4 times in the transverse direction at 220 to 240 ° C to prepare a biaxially oriented polyester film of the present invention.

3) Magnetic tape manufacturing

Iron oxide was dispersed as a magnetic material to prepare a magnetic dispersion.

Subsequently, the magnetic tape was applied to the polyester-based polyurethane resin of the prepared polyester film and then dried to prepare a magnetic tape of the present invention.

The performance evaluation results of the film and the magnetic tape prepared are shown in Table 1.

Example 2

The polyester film and the magnetic tape were prepared by repeating the procedure of Example 1 except that the solid content of the polyester-based polyurethane resin in the dispersion coating solution was 2% by weight. The performance evaluation of the film and the magnetic tape produced is shown in Table 1.

Example 3

The procedure of Example 1 was repeated except that the solid content of the polyester-based polyurethane resin in the dispersion coating solution was 5% by weight to prepare a polyester film and a magnetic tape. The performance evaluation of the film and the magnetic tape produced is shown in Table 1.

Example 4

The procedure of Example 1 was repeated except that the solid content of the polyester-based polyurethane resin in the dispersion coating solution was 10% by weight to prepare a polyester film and a magnetic tape. The performance evaluation of the film and the magnetic tape produced is shown in Table 1.

Example 5

The polyester film and the magnetic tape were prepared by repeating the procedure of Example 1, except that 0.2 parts by weight of silica particles having an average particle diameter of 1.0 μm was added instead of the calcium carbonate particles in polyester production. The performance evaluation of the film and the magnetic tape produced is shown in Table 1.

Comparative Example 1

The polyester film and the magnetic tape were prepared by repeating the procedure of Example 1 except that no dispersion coating solution was applied. The performance evaluation of the film and the magnetic tape produced is shown in Table 1.

Comparative Example 2

The procedure of Example 1 was repeated except that AC503 of Rohm and Haas was used as the water dispersible acrylic resin instead of the polyester-based polyurethane resin of Example 1 as the main component of the dispersion coating solution. And magnetic tape. Performance evaluation of the prepared film and magnetic tape are shown in Table 1.

Comparative Example 3

The polyester film and the magnetic tape were prepared by repeating the procedure of Example 1 except that the water-dispersible polyester resin was used instead of the polyester-based polyurethane resin of Example 1 as the main component of the dispersion coating solution. The performance evaluation of the film and the magnetic tape produced is shown in Table 1.

Comparative Example 4

The polyester film and the magnetic tape were manufactured by repeating the procedure of Example 1 except that 0.3 parts by weight of silica particles having an average particle diameter of 3.0 μm were contained in the inner body of the calcium carbonate particles during the manufacture of the polyester film. The performance evaluation of the film and the magnetic tape produced is shown in Table 1.

Surface roughness (Ra) (μm) Adhesive force with magnetic layer (g / 15mm) Example 1 0.012 680 Example 2 0.013 750 Example 3 0.015 700 Example 4 0.013 550 Example 5 0.018 620 Comparative Example 1 0.012 230 Comparative Example 2 0.014 300 Comparative Example 3 0.014 320 Comparative Example 4 0.052 650

As described above, the polyester film manufactured by the manufacturing method of the present invention has a low surface roughness and high adhesive strength with the magnetic layer, which is useful for producing a magnetic tape.

Claims (4)

The dicarboxylic acid component and the glycol component are polymerized to obtain a polyester resin, and the resin is melt-extruded to obtain an unstretched sheet, and at least 60% of the main repeating units prepared by biaxially stretching the sheet are ethylene terephthalate or In the biaxially oriented polyester film made of ethylene naphthalate, the film contains 0.01 to 2.0 parts by weight of particles having an average particle diameter of 0.01 to 2.0 µm and inert to the polyester, based on 100 parts by weight of the dicarboxylic acid component. And a polycarbonate prepared by copolymerizing a dicarboxylic acid component, a glycol component, the following general formula (I) and the following general formula (II) on at least one side of the polyester unstretched sheet or at least one uniaxially stretched polyester film: The dispersion coating liquid of ester-type polyurethane resin was apply | coated in the quantity of 0.01-0.5g / m <2> based on solid content. Characterized in that the biaxially oriented polyester film: Formula 1

Formula 2

Wherein R is a C _1-10 aliphatic hydrocarbon group, R ¹ , R ² and R ³ are independently of each other a C _1-5 alkyl group, n and m are each independently an integer from 1 to 5. The method of claim 1, The weight ratio of the polyester component and a polyurethane component in the said polyester-type polyurethane resin is 10: 90-90: 10, The film characterized by the above-mentioned. The method of claim 1, Dispersion coating liquid of the polyester-based polyurethane resin is a film, characterized in that prepared by dispersing 1 to 10% by weight of the resin and 0.01 to 0.5% by weight of the surfactant in water. Magnetic tape prepared by applying a magnetic layer on the surface of the polyester film of the polyester film prepared according to claim 1 is coated, and then dried.