KR100254477B1 - Method of producing biaxially streched polyester film - Google Patents

Abstract

PURPOSE: A process for preparing the tilted polyester film by adding a lubricating agent having high hardness and a globular lubricating agent or inactive particles to polyester is provided. Whereby obtained film has excellent runnability, abrasion resistance and scratch resistance. CONSTITUTION: This polyester film is characterized in that it contains 0.03 to 1% by weight of fine silica particles having a hardness of more than 6 and an average particle size of 0.03 to 0.2 micrometer and one or more of granular inorganic particles or inactive particles, wherein the inactive particles have an average particle diameter of 0.1 to 1.2 micrometer and a content of 0.05 to 1.0% by weight.

Description

Manufacturing method of biaxially oriented polyester film

The present invention relates to a method for producing a biaxially oriented polyester film, which will be described in more detail by adding high hardness lubricant and one or more inert particles to the polyester, or adding spherical inorganic particles together. A method for producing a biaxially oriented polyester film having improved abrasion resistance and scratch resistance.

Polyester, generally represented by polyethylene terephthalate, has a stable chemical structure and high mechanical properties, and is excellent in heat resistance, chemical resistance, and durability, and is not only used for capacitors, medical devices, packaging materials, photographic films, and labels. It is widely used for various purposes such as description of magnetic recording media.

Films made from such polyesters have a film surface in contact with a processing process, for example, a roll, which is in contact with an increasing process speed, for example, a printing process for packaging use, a magnetic material application for a recording medium, calendar ring, or slitting. Abrasion caused problems in post-processing and product characteristics (quality).

In particular, in the case of magnetic recording media, inert inorganic particles, such as calcium carbonate, silica, kaolin, and alumina, are added as lubricants to improve runability and processability of the film, thereby forming irregularities on the surface of the polyester film. There is a problem of deterioration of electronic characteristics due to roughening of the film surface.

Recently, the improvement of the electronic conversion characteristics according to the trend of high performance of the magnetic recording medium requires a film of a flat surface, and the coefficient of friction when the surface of the film is flattened to improve the electronic characteristics, which is one of the important requirements of these customers. Increasing the value of the driving performance is poor, on the contrary, roughening of the surface to improve the driving performance has the opposite result of lowering the electronic characteristics and wear resistance characteristics.

Therefore, it is required to develop a film that is excellent in both running characteristics, electronic characteristics, and wear resistance. Furthermore, as the tape production speed increases, the demand for driving characteristics, winding characteristics, scratch resistance, etc. at high speeds is also increasing. As the quality of tape decreases due to the use of low-cost materials for saving, the demand for durable films to prevent this is increasing.

Many patents have been known to improve the scratch resistance and abrasion resistance of films by adding high hardness lubricants, but are required for durability due to the increase in coarse particles due to the decrease in the dispersibility of the high hardness lubricant of fine particles or repeated use. Esau's effectiveness was somewhat lacking.

In the present invention, in order to solve the above problems, high hardness lubricant is added to the polyester to improve the hardness of the film and at the same time, spherical lubricant is added or inert particles are added to impart surface projections to improve driving characteristics. It is an object of the present invention to provide a method for producing a biaxially oriented polyester film with improved biaxially oriented polyester film, which has excellent running and abrasion resistance and good scratch resistance.

The present invention for achieving the above object contains 0.03 ~ 1% by weight of aerosol-based fine silica particles having an average particle diameter of 0.03 ~ 0.2㎛ having a warning of 6 or more in order to improve the hardness of the film in the polyester, in addition to the average particle diameter 0.05 to 0.3% by weight of the spherical inorganic particles of 0.1 to 1.5㎛ or 0.05 to 1% by weight of inert particles, characterized in that the polyester of the present invention is transesterification and direct exchange reaction Any method can be applied, and the reactor can use either batch or continuous type to produce a film that can satisfy both winding properties, running characteristics and electronic properties simultaneously.

Hereinafter, the present invention will be described in detail.

The present invention comprises 0.03 to 1% by weight of aerosol-based fine silica particles having an average particle diameter of 0.03 to 0.2 µm with a hardness of 6 or more in order to improve the hardness of the film in the polyester, and in addition, a spherical type having an average particle diameter of 0.1 to 1.5 µm. 0.05 to 0.3% by weight of inorganic particles or 0.05 to 1% by weight of inert particles. The method for producing a biaxially oriented polyester film characterized by the above-mentioned.

The polyester of the present invention contains at least 80 mol% of ethylene terephthalate repeating units and the remaining amount of the dicarboxylic acid component or the oxycarboxylic acid components as other copolymerization components. As said dicarboxylic acid, isophthalic acid, para- methoxyoxyethoxy benzoic acid, 2, 6- naphthalene dicarboxylic acid, 4, 4'- dicarboxy diphenyl, 4, 4'- dicarboxy bezophenone And bis (4-carboxydiphenyl) ethane, adipic acid, sefasin acid, 5-sodium sulfoisophthalic acid, and the like.

Examples of the oxycarboxylic acid include propylene glycol, butanediol, neopentyl glycol, butanediol, diethylene glycol, cyclohexanedimethanol, and paraoxybenzoic acid.

The polyester is typically a PET obtained by polycondensation of dicetyl terephthalate and ethylene glycol, and the polyester production method may be applied to any of a transesterification method and a direct exchange method, and the reactor may be either batch or continuous. It can be used either.

When carried out by the transesterification method, there is no restriction on the transesterification catalyst, and any conventionally known one can be used.

For example, the esner exchange catalyst may be soluble in the reaction system among alkaline earth metal compounds such as magnesium compounds, zirconium compounds, sodium compounds, potassium compounds, calcium compounds, and marium compounds, cobalt compounds, zinc compounds, and manganese compounds. It may be used, and the polymerization catalyst is also not limited, but may be suitably selected from antimony compounds, germanium compounds, and titanium compounds.

The fine silica particles or spherical inorganic particles and inert particles used in the present invention are inert particles with respect to polyester, and in the case of fine silica particles, the hardness is 6 or more in the aerosol type and the average particle diameter is 0.03 to 0.2 μm, preferably spherical. 0.03 ~ 0.1㎛ for inorganic particles of the type, 0.04 ~ 0.1㎛ for inert particles, 0.03 ~ 1% by weight, preferably 0.03 ~ 0.5% by weight for spherical inorganic particles, 0.05 inert diesel When it contains-0.5% by weight it can exhibit the effect of the present invention.

In the case of the spherical inorganic particles or inert particles, the component or type thereof is not particularly limited, but spherical inorganic particles generally have an average particle diameter of 0.1 to 1.5 μm in order to satisfy electronic characteristics, abrasion resistance, and runability. It is preferably in the range of 0.1 to 1.0 µm, and the amount thereof is generally in the range of 0.03 to 1.0% by weight, preferably 0.05 to 0.5% by weight.

In addition, in the case of inert particles, the average particle diameter and content are not particularly limited, but in order to satisfy electronic characteristics, abrasion resistance, runability, etc., the average particle diameter is generally in the range of 0.1 to 1.2 μm, preferably 0.3 to 1.0 μm, Is generally in the range of 0.05 to 1% by weight, preferably 0.1 to 1% by weight.

The mulberry particles used in the present invention are not particularly limited, but a composition of silita, calcium carbonate or alumina, or an organic polymer particle is preferable, and each inorganic particle may be surface treated.

In addition, the inert particles used in the present invention are not particularly limited, but are preferably composed of a composition of calcium carbonate such as synthetic calcium carbonate, inorganic particles such as spherical colloidal silica, or organic polymer particles. It may be done.

In the case of the spherical inorganic particles and the inert particles used in the present invention, the fine silica particles have a hardness of less than 6, which is insufficient to improve the hardness of the film surface, and the average particle diameter is 0.03 μm or less, or the amount of spherical inorganic particles In the case of 1% by weight, 0.5% by weight or more of inert particles are not preferred because the aggregation of the fine silica particles is severe and the drop out of the magnetic tape due to the formation of coarse particles appears.

On the other hand, when the particle diameter of the fine silica particles is 0.1㎛ or more, dropping is easy due to lack of affinity due to the hardness difference with the polymer, which may cause wear or scratch during post-processing or tape use, and the loading amount is 0.03% by weight or less. The improvement of the scratch resistance and durability of this invention is inadequate.

In addition, if the average particle diameter of the inert particles to be added is less than the claims, the surface roughness of the film is lowered, the friction coefficient is increased, runability is lowered, if it is more than the claims, the electronic properties are deteriorated, it is not preferable, the input amount of the injected particles is less than the claims If it is added to the roughening of the film is inadequate, and if it is added over the claims, it is not preferable because the drop out phenomenon of the magnetic tape due to the generation of coarse particles due to the flocculation phenomenon of the lubricants.

In particular, when the shape of the inorganic particles used in the present invention is a spherical shape, the inclination of the projections on the surface of the film increases the role of reducing the contact area, so the friction coefficient during driving decreases, and conversely, the inclination of the projections when the particle shape is not spherical. Since the contact area is increased and the friction coefficient tends to increase, when the spherical inorganic particles are added, a large amount of small particle size inorganic particles (A) is added, and a small amount of large particle sizes (B) are added. By adding the film to a specific surface shape, it is possible to obtain a film having both good scratch resistance and repeated durability while improving runability and electronic properties.

The polyester of the present invention is a PET obtained by polycondensation of dimethyl terephthalate and ethylene glycol, and in the preparation of such polyester, any of a transesterification method and a direct exchange reaction method may be applied, and the reactor may be either batch or continuous. Can be used.

In the case of the transesterification reaction, there is no restriction on the transesterification catalyst, and any conventionally known one can be used. For example, the transesterification catalyst may be any of alkaline earth metal compounds such as magnesium compounds, zirconium compounds, sodium compounds, potassium compounds, calcium compounds, barium compounds, cobalt compounds, zinc compounds, and manganese compounds that are soluble in the reaction system. Do.

The polymerization catalyst is also not limited but may be suitably selected from antimony compounds, germanium compounds and titanium compounds.

The polyester containing the inorganic particles prepared by the above method is sufficiently dried, melt-extruded and cooled by a Tie-die method or the like to form an unstretched sheet, followed by biaxial stretching. The manufacturing method of the film is not particularly limited, but after stretching 2.5-5.0 times in the longitudinal direction using the sequential biaxial stretching method, the stretching temperature is 3.0-5.0 times in the transverse direction, and the stretching temperature is higher than the Tg point or lower than the cold crystallization temperature. To produce a biaxially oriented polyester film of the present invention in the range of 180-230 ° C, preferably 190-220 ° C.

Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these Examples. In Examples and Comparative Examples of the present invention, various performance evaluation of the prepared polyester film was carried out by the following method, the results are as shown in Table-1 when containing spherical inorganic particles, inert If it contains at least one particle, it is as shown in Table-2.

1) Average particle size of particles (spherical inorganic particles and inert particles)

After the inorganic particles were dispersed in ethylene glycol, the volume average particle diameter (mu m) was measured using a centrifugal sedimentation particle size analyzer (SA-CP II) manufactured by Shimadzu Corporation.

2) Surface roughness (spherical inorganic particles and inert particles)

Surface roughness was measured using a contact surface roughness meter (SURFCORDER SE-30D) of Kosaka Research Institute (Japan). Measurement conditions The needle diameter = 2 µm, cut-off = 0.08 mm, measurement length = 5 mm, and 5 points after the measurement of 7 points were averaged.

3) Runability (Spherical inorganic particles)

Using a tape runability tester (TBT-300H) from Yokohama Systems Research Institute (Japan), a running friction coefficient k is obtained by running a film slit of 1/2 "width in a 20 ° C / 60RH% atmosphere as follows. .

k = 1n (T out / T in)

Where T in is the inlet tension and T out is the outlet tension.

A) low speed

After fixing the guide pin, the performance was measured using a contact angle of 180 degrees, a running speed of 3.3 cm / sec, and an inlet tension of 30 g. The running friction coefficient µk at low speed travel is 0.35 collimated, and it is good if it is less than it, and it is determined that it is bad.

B) High speed running

After the guide pins were solidified, the runability was measured at a contact angle of 180 degrees, a running speed of 50 cm / sec, and an inlet tension of 300 g. The running friction coefficient at high speed is based on 0.10, and if it is less than that, it is determined that it is good.

3) Wear resistance (inert particles)

Using the tape runability tester (TBT-300H) of Yokohama Systems Research Institute (Japan), the film was slit to a width of 1/2 inch, and then friction running on the tape guide pin at a running speed of 3.3 cm / sec. Abrasion resistance is evaluated by visually or photographing the powder on the surface of the powder.

Class A: If there is no powder at all on the guide pin,

Class B: If 100% of the guide pin is 1/5 of the guide pin area,

C class: If the guide pin has about 1/2 of the guide pin area,

Class D: If hundredths occur on the entire guide pin,

4) Coarse particles (inert particles)

The film of 100cm2 area was observed by the optical microscope, and the number of particle | grains of 1 micrometer or more was counted and compared.

5) Scratch resistance (inert particles)

Using the tape runability tester (TBT-300H) of the Yokohama Systems Research Institute (Japan), the film was slit to a width of 1/2 inch, and then friction running on the tape guide pin at a running speed of 2,300 m / min The degree of scratches was evaluated by visual or photographic observation.

Grade A: if there is no scratch on the film,

Class B: If the film has about 1/5 of scratches,

Grade C: If the film has about 1/2 scratch

Class D: If scratches occur on the entire film,

Various performance evaluation tables of the polyester film prepared by containing the spherical inorganic particles in the same manner as described above are as follows.

In addition, various performance evaluation tables of the polyester film prepared by containing two or more kinds of inert particles by the above method are as follows.

TABLE 1 Example 1

After preparing ethylene glycol slurry (A) containing 0.2% by weight of aerosol-based fine silica particles having an average particle diameter of 0.06 µm and ethylene glycol slurry (B) containing 0.4% by weight of 0.9 µm of synthetic calcium carbonate, respectively, dimethyl tere 7500 g of phthalate and 4780 g of ethylene glycol were transesterified after addition of the above ethylene glycol slurries in a batch reactor in the presence of 0.0224 wt% zinc acetate and 0.0404 wt% calcium acetate as a transesterification catalyst.

The above-mentioned transesterification material was subjected to polycondensation reaction with 0.0444% by weight of antimony trioxide as a polymerization catalyst to prepare a polyester polymer having a molecular weight of 20,000 and then dried at 180 ° C. for 8 hours, followed by melt extrusion by a tee-die method or the like. A non-oriented sheet was made by the method, stretched 3.1 times in the longitudinal direction and 3.7 times in the transverse direction at 90 ° C., followed by heat treatment at 210 ° C. to prepare a biaxially oriented polyester film having a thickness of 14 μm.

9 to 2 and Comparative Examples 1 to 6 in Table 2

Among the conditions of Example 1, the average particle diameter, the addition amount, and the addition amount ratio of the inorganic particles added during polymerization were changed to prepare films having characteristic differences, respectively.

The characteristics evaluation results of the films each containing spherical inorganic particles and inert particles are shown in Tables -1 and -2. When the particle diameters and protrusion heights of the inorganic particles and the inert particles specified in Tables 1 and 2 are within the scope of the claims of the present invention, it is possible to produce a film that can satisfy both the winding properties, the running properties, and the electronic properties simultaneously. .

As described above, the fine silica particles or spherical inorganic particles and the inert particles used in the present invention are inert particles with respect to the polyester, and in the case of the fine silica particles, the hardness is 6 or more in the aerosol type and the average particle diameter is 0.03 to 0.2 μm. Preferably it is 0.03 ~ 0.1㎛ for spherical inorganic particles, 0.04 ~ 0.1㎛ for inert particles, the dosage is 0.03 ~ 1% by weight, preferably 0.03 ~ 0.5% by weight for spherical inorganic particles, inert Particles containing 0.05 to 0.5% by weight of diesel may exhibit the effects of the present invention.

In particular, when the shape of the inorganic particles used in the present invention is a spherical shape, the inclination of the projections on the surface of the film increases the role of reducing the contact area, so the friction coefficient during driving decreases, and conversely, the inclination of the projections when the particle shape is not spherical. Since the contact area is increased to increase the friction coefficient during driving, a large amount of inorganic particles (A) having a small particle size are added, and a small amount of inorganic particles (B) have to be added. By adding the film to a specific surface shape, it is possible to obtain a film having both good scratch resistance and repeated durability while improving runability and electronic properties.

Claims (5)

Biaxial orientation, characterized in that the polyester contains 0.03-1% by weight of aerosol-based fine silica particles having a hardness of 6 or more and an average particle diameter of 0.03 to 0.2 µm, and one or more types of spherical inorganic particles or inert particles. Method for producing a polyester film. The method for producing a biaxially oriented polyester film according to claim 1, wherein the average particle diameter of the inert particles is 0.1-1.2 mu m, and the content is 0.05-1.0 wt%. The method for producing a biaxially oriented polyester film according to claim 1 or 2, wherein the inert particles are a composition such as synthetic calcium carbonate, spherical colloidal silica and organic polymer particles. The method for producing a biaxially oriented polyester film according to claim 1, wherein the average particle diameter of the aqueous phase inorganic particles is inorganic particles of spherical colloidal silica or synthetic calcium carbonate of 0.1-1.5 탆. The method for producing a biaxially oriented polyester film according to claim 1 or 4, wherein the input amount of the spherical inorganic particles is 0.03-1.0 wt% based on the polyester.