KR100192081B1 - Process for the preparation of polyester film - Google Patents

Abstract

The present invention relates to a polyester composition comprising 0.01 to 2.0 parts by weight of a plate-like particle having an average particle size of 0.01 to 2.0 占 퐉 insoluble in polyester, and 0.01 to 1.0 parts by weight of spherical particles having an average particle size of 0.1 to 3.0 占 퐉 insoluble in polyester, The present invention relates to a method for producing a polyester film which does not cause contamination of the head even when used in a high-speed copying machine due to no dropout of particles during high-speed copying.

Description

Method for producing polyester film

More specifically, the present invention relates to a method for producing a polyester film excellent in lubricity and abrasion resistance by containing specific inorganic particles and excellent in high-speed running property when it is produced from a magnetic tape.

Since the saturated linear polyester film typified by polyethylene terephthalate has excellent mechanical properties, heat resistance, weather resistance, electrical insulation, chemical resistance, and the like, it can be used in various fields such as soil application, photographic use, It is widely used.

In general, in order to smoothly use a polyester film for each application, the effect of winding workability and post-processing fairness on the quality of the final product is great, and the reactivity of the film is one of properties that are particularly important.

A method of imparting fine unevenness to the surface of a film is widely used in order to improve the smoothness of the film. As a method for imparting unevenness to the surface of a film, a method of adding inert inorganic particles such as calcium carbonate, silica, alumina, kaolin and the like to the reaction system in the production of polyester is most widely used. Further, there is a method of precipitating fine particles in the reaction system by using a residue of a metal compound used as a catalyst in the polymerization. For example, JP-A-34-5144 discloses a method in which a compound of an alkaline earth metal is added with phosphoric acid or its ester To control the friction characteristics of the film.

In addition, it is also known that inert microparticles are added in an extrusion process in the production of a film to form protrusions on the surface of the film to impart reactivity.

On the other hand, in the production of a large number of image and music publications by manufacturing a polyester film with a magnetic tape, as the copying speed is increased due to the recent development of the technology, the particles are easily dropped off due to friction with the polyester film as the tape base, The particles are liable to cause problems such as contamination of the head of the copying machine and the like, thereby causing a decrease in productivity. Recently, a method has been proposed in which organic particles having excellent affinity with polyester are added to reduce voids and impart lubricity. For example, in Japanese Patent Application Laid-Open Publication No. 90-11640, in order to improve low abrasion resistance due to lack of affinity between polyester and inorganic particles in the production of polyester film, silicone polyimide, crosslinked styrene-divinylbenzene copolymer , Crosslinked polyester, and Teflon, and an inorganic lubricant such as calcium carbonate. However, the organic particles have not yet reached a satisfactory level due to their insufficient strength.

Disclosure of the Invention The present inventors have conducted intensive studies to develop a polyester film which has excellent lubricity and abrasion resistance and which does not cause particle drop off even at the time of high-speed radiation when it is produced by a magnetic tape. As a result, It has been found that a film having the above-described characteristics can be produced by adding an insoluble particle to an appropriate amount of a polyester film, thereby completing the present invention.

Therefore, in the present invention, in the method for producing a polyester film having repeating units of ethylene terephthalate or ethylene naphthalate, 0.01 to 2.0 parts by weight of a plate-like particle insoluble in polyester having an average particle diameter of 0.01 to 2.0 占 퐉, And 0.01 to 1.0 parts by weight of spherical particles having an average particle diameter of 0.1 to 3.0 占 퐉.

The average particle diameter of the tabular grains to be added in the production of the polyester film of the present invention is 0.01 to 2.0 占 퐉, and more preferably 0.1 to 1.5 占 퐉. If the average particle diameter is larger than 2.0 占 퐉, the surface of the polyester film becomes roughened and the electronic characteristics become poor. If the average particle diameter is smaller than 0.01 占 퐉, the size of the irregularities formed on the surface of the film becomes too small.

When the content is less than 0.01 parts by weight, the number of irregularities formed on the surface of the film becomes small, resulting in poor lubricity. If the content is more than 2.0 parts by weight, the film becomes roughened.

The plate-like particles to be used in the present invention include, for example, plate-like kaolin, mica, plate-like silica, plate-like calcium phosphate, boron nitride, talc, synthetic mica and the like, May be used within the range not adversely affecting the object of the present invention.

In the production of the polyester film of the present invention, spherical particles to be added together with the above-mentioned platelet-shaped particles preferably have an average particle diameter of 0.1 to 3.0 탆 and more preferably 0.3 to 2.0 탆. If the average particle diameter is larger than 3.0 占 퐉, the surface of the polyester film is roughened to deteriorate the electronic characteristics. If the average particle diameter is smaller than 0.1 占 퐉, the size of the irregularities formed on the surface of the film becomes too small.

When the content is less than 0.01 parts by weight, the spherical particles are contained in an amount of 0.01-1.0 parts by weight. When the content of the spherical particles is less than 0.01 parts by weight, the number of unevenness formed on the surface of the film is low, .

The spherical particles to be used in the present invention include, for example, spherical silica, spherical alumina, spherical calcium carbonate, spherical titanium dioxide, polystyrene, silicone rubber, and the like, Any of which may be used within the range not adversely affecting the object of the present invention.

In order to further enhance the effect of the present invention, inorganic or organic particles insoluble in polyester are preferably used in addition to the above-mentioned plate-like and spherical particles. The particles that can be used in this way may be selected from any particles that form suitable irregularities in consideration of the object of the present invention and the characteristics of the magnetic tape to be used, and two or more kinds of particles may be mixed and used.

In order to improve the affinity with the compact, it is also possible to subject the tabular and spherical particles to a surface treatment with a known surface treatment agent.

In the production process of the present invention, the method of adding the plate-like and spherical particles is not particularly limited, and it is possible to add the plate-like and globular particles and the combined particles at an arbitrary point in time before the completion of the polymerization reaction by using a conventionally known method desirable.

In the present invention, a method for producing a film using polyester, a plate-like or globular particle, a combined particle and other additives is not particularly limited, and a conventional known film production method can be used. For example, a continuous sheet can be produced by adhering a plate-like polymer to a cooling drum rotating the dried polyester using an extruder. The thus-prepared sheet is subjected to a longitudinal stretching process, and any one of a single-stage or multi-stage stretching method may be used. In-line coating may be performed between the longitudinal stretching and the transverse stretching in order to improve the adhesion of the film, antistatic property, or the like, and the corona treatment may be performed after the transverse stretching.

Hereinafter, the present invention will be described in detail with reference to examples. However, the scope of the present invention is not limited to the following examples.

The measurement methods used in the examples are as follows.

1) Average particle size and particle shape

50 parts of the particles were photographed with a scanning electron microscope (magnification: 50,000), and then the particle size of each part was measured by an image analyzer and arithmetically averaged, and the shape of each particle was classified into a plate shape, a spherical shape, Respectively.

Plate: When the width / thickness of particles is 3 and the length / thickness is 3

Concept: Circular particles with 0.9 width / height / thickness 1.1

Mass: 0.5 Width / Thickness 3 and 0.5 Length / Thickness 3

2) Active

Using a TBT-300D tape running tester of the Yokohama System Research Institute, Japan, a tape slit with a 1/2 inch width was used to set a traveling speed of 3.3 cm / sec and a pulling tension of 30 g, The running friction coefficient was measured from the winding tension when the pin (material SUS303) was passed through 90 m using the following equation:

? k = [2.308 /?] x log [T _i / T _o ]

here,

θ: Contact angle of film and guide pin

T _i and T _o are the pull-in tension and the winding tension, respectively

3) Abrasion resistance

The degree of the amount of the white powder adhering to the fixed guide pin at the point of time when the measurement of the lubricity was released was evaluated in the following four steps:

Little to no hundred percent: ㉠

1 to 5% of guide pin area: 0

5 to 10% of guide pin area: △

More than 10% of the guide pin Area: x

[Example 1]

100 parts of dimethyl terephthalate, 70 parts of ethylene glycol and 0.05 part of calcium acetate were put into a reactor and ester exchange reaction was carried out. 4 hours later, in the system in which the transesterification reaction was actually completed, tabular kaolin particles having an average particle diameter of 0.4 탆 and spherical silica particles having an average particle diameter of 0.5 탆 were contained in an amount of 0.3 part by weight and 0.01 part by weight, respectively, per 100 parts by weight of polyester After the addition, 0.06 part of trimethyl phosphate and 0.04 part of antimony trioxide were added and polymerization reaction was carried out for 5 hours by a conventional method to obtain a polyester.

The polyesters were dried and then closely contacted with a cooling drum rotating at 290 ° C with a sheet extruder to obtain an amorphous sheet. Thereafter, the film was stretched 3.5 times at 90 占 폚 in the longitudinal direction and 4.3 times at 110 占 폚 in the transverse direction, and heat-treated at 210 占 폚 for 3 seconds to obtain a film having a thickness of 15 占 퐉.

As a result of the analysis of the film obtained above, as shown in Table 1, the lubricity and the abrasion resistance were good, and the high-speed driving performance was good when the videotape was manufactured.

[Example 2]

Except that 0.2 part by weight of plate-like mica particles having an average particle diameter of 0.6 mu m and 0.05 part by weight of spherical alumina particles having an average particle diameter of 0.8 mu m were added, Respectively.

[Example 3]

A film was prepared in the same manner as in Example 1, except that 0.2 part by weight of the plate-like mica particles having an average particle diameter of 0.6 탆 and spherical organic silicon particles having an average particle diameter of 0.5 탆 were added so as to contain 0.3 part by weight, Are shown in Table 1.

[Example 4]

A film was prepared in the same manner as in Example 3, except that 0.1 part of massive calcium carbonate particles having an average particle diameter of 0.5 탆 was further added. The evaluation results are shown in Table 1.

[Comparative Example 1]

Except that 0.3 mass part of massive calcium carbonate having an average particle diameter of 0.5 占 퐉 was added instead of the plate-like kaolin and spherical silica particles, and the evaluation results were shown in Table 1 Respectively.

[Comparative Example 2]

A film was prepared in the same manner as in Example 1, except that only 0.3 part by weight of the sheet-like kaolin particles having an average particle diameter of 0.5 μm was added. The evaluation results are shown in Table 1.

[Comparative Example 3]

A film was prepared in the same manner as in Example 1, except that only 0.3 part by weight of spherical silica particles having an average particle diameter of 0.5 탆 was added. The evaluation results are shown in Table 1.

[Comparative Example 4]

A film was prepared in the same manner as in Example 1, except that 0.3 part by weight of the sheet-like kaolin particles having an average particle diameter of 0.5 mu m and 0.1 part by weight of a massive calcium carbonate particle having an average particle diameter of 0.8 mu m were added. The evaluation results are shown in Table 1.

As described above, according to the present invention, 0.01-2.0 parts by weight of a plate-like particle having an average particle diameter of 0.01-2.0 mu m insoluble in polyester and 100-2.0 parts by weight of a spherical phase insoluble in polyester having an average particle diameter of 0.1-3.0 mu m Type particles are added, it is possible to produce a polyester film which does not cause contamination of the head even when used in a high-speed copying machine due to its excellent lubricity and abrasion resistance and does not cause particle dropping during high-speed copying, The produced film can be widely used for various applications requiring friction and abrasion resistance in addition to magnetic tape.

Claims (1)

A process for producing a polyester film having repeating units of ethylene terephthalate or ethylene naphthalate, comprising the steps of: 0.01-2.0 parts by weight of a plate-like particle having an average particle diameter of 0.01-2.0 mu m insoluble in polyester with respect to 100 parts by weight of polyester; And 0.01 to 1.0 part by weight of spherical particles having an average particle diameter of 0.1-3.0 mu m insoluble in said particles.