KR19990065002A - Highly transparent biaxially oriented polyester film - Google Patents

Abstract

The present invention is based on the finding that the physical properties such as mechanical strength, thermal properties, electrical properties, chemical resistance,

Polyester which is widely used for industrial purposes such as packaging, lamination, window, etc.

The film is excellent in transparency as compared with conventional products, and has a very good winding property.

In order to achieve the above object, the present invention provides a process for esterifying at least one carboxylic acid and at least one glycol component,

0.005 to 0.1 wt% of precipitated silica particles having a diameter of 10 to 40 nm,

By adding 0.001 to 0.01 wt% of cubic-shaped synthetic calcium carbonate having a narrow particle size distribution range, mixing the resulting polyester with a polycondensate, drying, melting, extruding,

And a biaxially stretched polyester film excellent in windability.

Description

Highly transparent biaxially oriented polyester film

INDUSTRIAL APPLICABILITY The present invention is excellent in transparency and winding property and can be used for laminate, packaging, window,

The present invention relates to a biaxially oriented polyester film suitable for use in the manufacture of a polyester film, and more particularly to a biaxially oriented polyester film suitable for use in the manufacture of a polyester film, which comprises a polyester film having small projections formed of particles having excellent transparency, By forming

And a biaxially oriented polyester film excellent in fame and spinnability.

The polyester film has excellent physical and chemical properties and is widely used in industry

In particular, it has excellent mechanical strength, thermal properties, electrical properties, chemical resistance, moisture resistance and water resistance

It is widely used in packaging, industrial, and magnetic applications. In particular, to improve the transparency of the film

In order to minimize the amount of inorganic inert particles added during polyester production

However, since transparency can be secured to a certain level,

Resulting in a deterioration of the wound state and deterioration of the yield of production.

In order to solve the above problem, Japanese Patent Application Laid-Open No. 53-45396

JP-A-59-206456 discloses a method of using a variety of particles and a higher fatty acid amide compound, but in the case of the former,

It is necessary to use a large amount of particles in order to secure the winding-up property,

In the case of the polyester film itself, the transparency of the polyester film is deteriorated,

There is a problem that the heat resistance of the polymer itself is deteriorated when using the imide compound.

In order to solve the above problems, the present invention provides a biaxially oriented polyester film

We select particles with excellent transparency and adjust the size of these particles to a certain size

By adding particles having a narrow particle size distribution range, a biaxially oriented polyester film excellent in transparency and winding property can be obtained.

In order to accomplish the above object, the present invention provides a method for producing a polyester resin by reacting one or more kinds of carboxylic acid and at least one glycol component with an ester and reacting with a preliminarily mixed silica having a primary particle diameter of 10 to 40 nm, Particles and narrow particle size distribution

After the addition of synthetic calcium carbonate, the polyester obtained by condensation polymerization is dried, melted and pressed

Followed by stretching, drawing and stretching. This will be described in detail below.

In the present invention, polyester is obtained by using an aromatic dicarboxylic acid such as terephthalic acid, 2,6-naphthalic acid dicarboxylic acid or the like or an ester compound thereof and ethylene glycol as starting materials

But another third component can be used. At this time, the starting material

As the dicarboxylic acid component, for example, terephthalic acid, 2,6-naphthalenedicarboxylic acid,

One or two kinds of acidic components such as deacidification, isophthalic acid, adipic acid and sebatic acid,

And examples of the glycol component include ethylene glycol, propylene glycol, butanediol,

1,4-cyclohexane dimethanol, neopentyl glycol, and the like. However, in the present invention, it is preferable to use a polyester in which 80% or more of repeating structural units are composed of ethylene terephthalate or ethylene 2,6-naphthalate structure

And shows superior characteristics.

The polyester produced by the present invention may contain heat stabilizers, anti-blocking agents, antioxidants,

An antistatic agent, an ultraviolet absorber, and the like.

The polyester film in the present invention refers to a polyester film which is biaxially oriented with polyester as a starting material, and a known method can be used for the production of the polyester film.

For example, at 270 to 300 캜, and then cooled and solidified at 40 to 70 캜 to obtain an amorphous unstretched film, which is subjected to longitudinal stretching at a temperature of 90 to 120 캜 at 3.0 to 4.0 times, After lateral stretching at 3.0 to 5.0 times, heat treatment is performed at 200 to 240 캜 to obtain a polyester film.

The most remarkable feature of the present invention is that a sodium silicate

Silicate: Na2O · nSIO2) was treated with sulfuric acid to produce primary particles

particle size) of 10 to 40 nm and an average particle diameter of 2.0 to 10 [micro]

The polyester film having excellent transparency can be obtained by adjusting the thickness to 0.01 to 1.6 탆

Can be obtained. The silica is generally produced by a method such as a fumed process,

(Geled Process), Precipitated Process (Precipitated Process)

Silica prepared by sedimentation method is most transparent. The silica prepared by the sedimentation method

Containing 0.05 to 3.5 parts by weight of Na ₂ S0 ₄ and above to the content of Na ₂ S0₄ less than 0.05 parts by weight

It is disadvantageous from the viewpoint of economical efficiency. When the amount is 3.5 parts by weight or more,

The durability of the ter is deteriorated.

The content of precipitated silica particles in the polyester film is preferably about 0.005 to 0.1% by weight. mouth

When the content of the inorganic fine particles is more than 0.1% by weight, the desired transparency can not be obtained,

%, The winding property is deteriorated and a projection on the film roll is generated, which is not preferable. If the particle diameter is not adjusted within the above range, for example, if the average particle diameter is 1.6

If it is more than 탆, macromolecular particles are present and large defects are formed on the surface of the film.

All.

Examples of the particle size regulating method include a BEAD filling method, a Dyno-Mill method,

It is advantageous to use the formula-wet method. Further, as the second particle component,

1.7 to 3.0 占 퐉, and a cumulative volume D ₉₀ / D ₁₀ ratio from a small particle size of 2.3

And 0.001 to 0.01 wt% of a cubic calcium carbonate particle. The calcium carbonate particles used here are obtained by the reaction between caustic soda (Na ₂ CO ₃ ) and calcium chloride (CaCl ₂ ).

If the D ₉₀ / D ₁₀ ratio is larger than 2.3, very large particles will be present and defects on the film surface

It becomes bad and becomes bad.

As the surface treatment agent of calcium carbonate, an acid form or a metal salt or ammonium salt form of a copolymer of acrylic and methacrylic is used.

The present invention relates to precipitated silica particles having an appropriate particle size and a particle size distribution

And the polyester obtained by polycondensation after addition of heptious calcium carbonate having a narrow range of

Extruded and stretched by the method of < RTI ID = 0.0 >

.

The following is a method for measuring the effect of the invention.

(1) average particle diameter of particles

The particle slurry was measured using a particle size distribution analyzer (Granulometer HR-850) of a laser diffraction method, and the particle size of 50% of the accumulated volume from the small particle size was calculated as spherical shape . The particle diameters at which the cumulative volume from small particle size is 10% and 90% are defined as D ₁₀ and D ₉₀ , respectively.

(2) turbidity (haze)

In order to measure the transparency, the polyester film was cut into a size of 3.5 inch × 3.5 inch, and one piece was placed vertically on a haze meter (Automatic Digital Hazemeter, manufactured by Nippon Denshoku)

And a light having a wavelength of 589 nm is transmitted through the sample in the vertical direction. The turbidity value

Calculate using the following formula. The measurement method was based on JIS-Z8722.

Turbidity (%) = (total scattered light / total transmitted light) × 100

(3) Wettability of the film

Cutting a wide-width poly-film roll with a narrow roll of 1000 mm width - During the SLITTING process

Determine the extent of the pimples on the small roll with the naked eye.

A: Small roll roll failure rate due to occurrence of pimple Less than 5%

B: Small roll roll defective rate due to occurrence of pimple Within 5 ~ 20%

C: Defect ratio of small roll roll caused by occurrence of pimple Within 20-40%

D: A small roll roll failure rate of 40% or more due to the occurrence of pimples

The following examples and comparative examples illustrate the present invention in more detail, but do not limit the present invention.

Example 1

100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 0.09 parts by weight of manganese

Acetate tetrahydrate and 0.04 part by weight of antimony trioxide were placed in a reactor and methanol

And the ester exchange reaction is carried out. After the transesterification reaction is complete,

0.06 part by weight of trimethyl phosphate in water and 15 parts by weight of precipitated silica

1.0 part by weight of the particles were added in the form of an ethylene glycol slurry and subjected to a polycondensation reaction

To obtain a polyester (A) having an intrinsic viscosity of 0.62.

In the same manner as above, a non-particle polyester having an intrinsic viscosity of 0.62

(C) is obtained.

The polyester (A) and the polyester (C) synthesized above were mixed at a weight ratio of 4:96 and then dried,

And cooled and solidified at 40 to 70 DEG C to obtain an amorphous undrawn film,

Longitudinal stretching 4.0 times at 120 占 폚, transverse stretching 4.5 times at 180-220 占 폚, and heat treatment at 220 占 폚 to prepare a 50 占 퐉 biaxially stretched polyester film

Respectively.

Example 2

The reaction is carried out in the same manner as the polyester (A), and the precipitated silica

Instead of the particles, a cubic-shaped D ₉₀ / D ₁₀ ratio of 1.84, an average particle diameter of 2.4 μm, synthetic calcium carbonate

And 0.1 part by weight of a polyol having an intrinsic viscosity of 0.62

(B).

The properties of the particles and the biaxially stretched polyester film using the stomach particles (A) are shown in Table 1

Is shown.

Example 3

The procedure of Example 1 was repeated except that precipitated silica particles having a pullulan particle size of 1.2 탆 were used.

The polyester (A) was similarly prepared. When the thickness of the particles and the particles (B)

Properties of the axially stretched polyester film are shown in Table 1.

Comparative Example 1

Except that silica particles produced by a gel (GEL) method having an average particle diameter of 1.8 占 퐉 were used

A polyester (A) was prepared in the same manner as in Example 1. Biaxial stretching using these particles

The properties of the polyester film are shown in Table 1.

Comparative Example 2

The procedure of Example 1 was repeated except that dry silica particles whose average particle diameter was adjusted to 0.4 탆 were used.

The polyester (A) was prepared in the same manner. The biaxially stretched polyester

The properties of the film are shown in Table 1.

Table 1

As confirmed in the above Examples and Comparative Examples, the biaxially oriented polyester film

Is superior in transparency and winding property and can be used for packaging, lamination, window or gold

And showed characteristics suitable for quietness.

Claims (3)

One or more carboxylic acids and one or more glycol components are reacted with ester groups And a precipitated silica raw material having a primary particle size of 10 to 40 nm and an average particle size of 0.01 to 1.6 탆 0.005 to 0.1% by weight, calcium carbonate particles having an average particle diameter of 1.7 to 3.0 占 퐉 as auxiliary particles, 0.001 to 0.01% by weight based on the total weight of the biaxially orientated polyester Terfilm. The method according to claim 1, The precipitated silica particles contain 0.05 to 3.5 parts by weight of Na2SO4. Biaxially oriented polyester film. The method according to claim 1, The calcium carbonate particles are cubic-shaped synthetic calcium carbonate having a cumulative volume ratio D ₉₀ / D ₁₀ of 2.3 or less Features a highly transparent biaxially oriented polyester film.