JPH01161025A - Biaxially oriented polyester film - Google Patents

Abstract

PURPOSE:To form a biaxially oriented polyester film having excellent surface flatness, slip properties, and anti-scraping characteristics, by compounding an arom. polyester and porous fine silica particles having a spherical shape close to a real sphere, a small particle size and a large specific surface area, molding the mixture into a film and drawing biaxially the film. CONSTITUTION:This biaxially oriented polyester film is formed by molding a dense mixture of an arom. polyester [1] and 0.005-4wt.% spherical porous fine silica particles [2] based on the wt. of the arom. polyester having a particle size ratio (a) defined by the radio of the max. diameter to the min. diameter, of 1.0-1.2, a mean particle size (b) of 0.01-4mum and a specific surface area (c) measured by the BET method of 70m<2>/g or larger. The said spherical porous fine silica particles are obtd. by, e.g., treating zeolite (Na2O.2SiO2.Al2O3.nH2O) with an acid to dissolve and remove the alumina component.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a biaxially oriented polyester film, and more specifically to a biaxially oriented polyester film having a specific surface area (BET method) of 70 as an effective lubricant component.
The present invention relates to a biaxially oriented polyester film that contains spherical porous silica particles of m/(] or more, is flat, slips, and has excellent abrasion resistance.

[Prior Art] Polyester, represented by polyethylene terephthalate, is used for magnetic tapes, photographs, and capacitors because of its excellent physical and chemical properties.

Widely used as packaging film.

The slipperiness and abrasion resistance of these J3 films are major factors that determine the workability of the film during the manufacturing process and various uses, as well as the quality of the product. In particular, when a magnetic layer is applied to the surface of a polyester film, the friction and abrasion between the coating roll and the film surface is extremely severe, and wrinkles and scratches are likely to occur on the film surface. In addition, even after the film is slit and processed into audio, video, or computer tapes, many guide parts and Abrasion occurs between the playback head and the like, resulting in scratches, distortion, and the precipitation of white powdery substances due to scratches on the surface of the polyester film, resulting in large dropouts of magnetic recording signals. It is often the cause.

In general, to improve the slipperiness and abrasion resistance of films, methods are used to reduce the contact area between the film and guide rolls by adding irregularities to the surface of the film. A method of precipitating inert fine particles from the catalyst residue of the polymer used, and (ii) a method of adding inert fine particles are used. Generally, the inert fine particles in these raw polyesters have a large serration effect that greatly improves the slipperiness, but for precision applications such as magnetic tapes, especially videos,
The large size of the particles itself can cause defects such as dropouts, so the unevenness on the film surface must be as fine as possible. It is in a state of

[Objective of the Invention 1 An object of the present invention is to provide a biaxially oriented polyester film having excellent surface flatness, ease of slipping, and abrasion resistance.

Another object of the present invention is to provide a biaxially oriented polyester film that has a large number of fine protrusions made of spherical porous silica particles on the film surface and has excellent surface flatness, easy slipperiness, and abrasion resistance. I'm in the middle of the day.

Further objects and advantages of the present invention will become apparent from the description below.

[Configuration and Effects of the Invention] According to the present invention, the above-mentioned advantages and advantages of the present invention are as follows: (1) aromatic polyester; and (2) (a) ratio of maximum diameter to minimum diameter; the defined particle size ratio is 1.0 to 1.2, (b) the average particle size is 0.01 to 4 μm, and (C)
A biaxially oriented polyester film obtained by molding an intimate mixture consisting of 0.005 to 4% (based on aromatic polyester) spherical porous silica fine particles having a specific surface area of 70 rrt/g or more by the BET method. achieved by

The aromatic polyester in the present invention is a polyester containing an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component. Such polyesters are substantially linear and have film forming properties, particularly by melt forming. Aromatic dicarboxylic acids include, for example, terephthalic acid, naphthalene dicarboxylic acid, isophthalic acid, diphenoxyethane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, anthracene dicarboxylic acid, etc. . Aliphatic glycols include, for example, ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, and hexamethylene glycol.

Alkylene glycols having 2 to 10 carbon atoms such as decamethylene glycol or alicyclic diols such as cyclohexane dimetatool are used.

In the present invention, as the aromatic polyester, for example, one containing alkylene terephthalate and/or alkylene naphthalate as a main component is preferably used.

Among such polyesters, of course there are polyethylene terephthalate and polyethylene-2,6-naphthalate, and for example, 80 mol% or more of the total dicarboxylic acid component is terephthalic acid and/or 2,6-naphthalenedicarboxylic acid. Particularly preferred are copolymers in which 80 mol% or more of the glycol component is ethylene glycol.

In this case, 20 mol% or less of the dicarboxylic acid of the acetic acid component can be the above-mentioned aromatic dicarboxylic acids other than terephthalic acid or 2,6-naphthalene dicarboxylic acid, and can also be aliphatic dicarboxylic acids such as adipic acid, cepatic acid, etc. It can be an alicyclic dicarboxylic acid such as dicarboxylic acid dichlorohekirin-1,4-dicarboxylic acid. In addition, up to 20 mol% of the glycol component can be the above-mentioned glycols other than ethylene glycol, or aromatic diols such as hydroquinone, resorcinol, 2,2°-bis(4-hydroxyphenyl)propane, etc. ;1.4
- Aliphatic diols having an aromatic ring such as dihydroxymethylbenzene; polyalkylene glycols (polyoxyalkylene glycols) such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. can also be used.

In addition, the aromatic polyester used in the present invention may contain a component derived from an oxycarboxylic acid such as an aromatic oxyacid such as hydroxybenzoic acid; a dicarboxylic acid component such as an aliphatic oxyacid such as ω-hydroxycaproic acid, or a dicarboxylic acid component. Also included are those containing 20 mol% or less based on the total amount of oxycarboxylic acid components.

In general, the aromatic polyester in the present invention contains an amount in a substantially linear range, for example, 2 mol % based on the aromatic acid component.
Also included are those copolymerized with tri- or more functional polycarboxylic acids or polyhydroxy compounds, such as trimellitic acid, pentaerythritol, etc., in the following amounts.

The above-mentioned aromatic polyester is known per se, and can be produced by a method known per se.

The above-mentioned aromatic polyester preferably has an intrinsic viscosity of about 0.4 to about 1.0 measured as a solution in O-chlorophenol at 35°C.

The biaxially oriented polyester film of the present invention has many fine protrusions on its surface.

According to the present invention, these many fine protrusions are derived from a large number of spherical porous silica fine particles dispersed and contained in the aromatic polyester.

The spherical porous silica fine particles according to the present invention are characterized by having characteristics such as (a) a spherical shape close to a true sphere, (b) a small particle size, and (C) a large specific surface area. and (d) narrow particle size.

That is, the spherical porous silica fine particles have (a) a particle size ratio defined by the ratio of the maximum diameter to the minimum diameter in the range of 1.0 to 1.2, and (b) an average particle size of 0.01 to 1.2. 4 μm, and (C) specific surface area (BET method) of 70 TIl/g or more. The above particle size ratio is preferably 1.
It is in the range of 0 to 1.15, particularly preferably 1.0 to 1.
．． It is in the range of 12. The above average particle size is preferably 0.0
It is in the range of 5 to 2 μm, particularly preferably 0.01 to 1
It is in the μm range.

Historically, the above-mentioned spherical porous silica fine particles have a relative standard deviation (σ) of the particle size defined by the following formula (A): 065 or less, further 0.3 or less, especially 0.12 or less. It is preferable that there be. Here, the area circular diameter means the diameter of each particle when converted into a perfect sphere.

If the above-mentioned relative standard deviation (σ) is 6<0.5 or less,
The spherical porous silica fine particles have an extremely sharp particle size distribution, and together with their spherical shape similar to pearls, they give the film surface protrusions that are extremely uniform in height and sharp in shape.

For this reason, the same number of protrusions provides a film with extremely good sliding properties, compared to conventional films with protrusions of uneven height and a more gentle shape.

In addition, the specific surface area is large, 70rd/g or more, 1TIj
The product is extremely active and can be subjected to various surface modification treatments, making it possible to further improve the ability to mix with polynisdel.

As long as the spherical porous silica particles satisfy the above-mentioned characteristics, there are no limitations on the manufacturing method or other characteristics.

For example, zeolite (Naz 0
・2SiOz ・Aj! 20. A spherical porous wrinkle strength can be obtained by precipitating crystals of + .nHzo and treating this biolite with acid to elute and remove the alumina component. There are no particular restrictions on the acid used here;
It can be an inorganic acid or an organic acid, but nitric acid.

Sulfuric acid, hydrochloric acid, phosphoric acid, etc. can be preferably used.

The shape of the above-mentioned spherical porous silica fine particles only needs to be truly spherical in the final stage of preparation, and the starting material Biolye 1 to 1 may be truly spherical, or it may be one that has been adjusted to a true spherical shape after acid treatment.

As mentioned above, the spherical porous silica fine particles of the present invention have individual spherical shapes very similar to pearls, and have a large specific surface area of 70 TIi/g or more, and have a specific surface area that is conventionally known as a lubricant. It is significantly different from lumpy porous silica with an irregular shape of about 200 m/CI, aerosol, colloidal silica, and silica particles with a smooth surface with a specific surface area of about 10 to 40 m/() even if they are truly spherical. The points are distinctive.

Aromatic polyester and spherical pores forming the film of the present invention? The intimate mixture with silica microparticles contains from 0.005 to 4.0% by weight (based on the aromatic polyester) of the microparticles. If the amount of the fine particles is less than 0.005% by weight, the effect of improving the slipperiness and abrasion resistance of the film will be insufficient, while if it exceeds 4.0% by weight, the flatness of the film will decrease. The amount of the fine particles is 0.01 to 2.0% by weight.
(vs. aromatic polyester) is preferred.

Polyester films containing such spherical porous silica particles have uniform uneven surface characteristics, excellent slipperiness and abrasion resistance, and are characterized by significantly less occurrence of scratches, white powder, etc. have

The reason for this feature, especially the excellent slipperiness and abrasion resistance, has not yet been fully elucidated.

As described above, since spherical porous silica particles have excellent characteristics, according to the present invention, they can be used in combination with other inert particles to improve runnability while having the advantage of using two or more types of particles. It has become clear that it is possible to provide a film with excellent abrasion resistance, fatigue resistance, electrical insulation, transparency, etc.

'? 1, such a biaxially oriented polyester film comprises: (1) an aromatic polyester; (2) (a) a particle size ratio defined by the ratio of the maximum diameter to the minimum diameter of 1.0 to 1.2; (b) The average particle size is 0.01 to 4 μm, and (c)
Spherical porous silica fine particles with a specific surface area of 70 TrL/g or more by the BET method (based on aromatic polyester), and (3) an average particle size of 0.01-4 μm. Inert particles that are 0
, 005 to 4% by weight (based on the aromatic polyester).

The aromatic polyester (1) and the spherical porous silica fine particles (2) are as described above.

The inert fine particles (3) used are those that are substantially inactive and insoluble in the aromatic polyester and are solid at room temperature. These may be externally added particles (A) or internally generated particles (8). Further, for example, a metal salt of an organic acid may be used, or an inorganic substance may be used. Preferred externally added inert particles (A) include: (1) calcium carbonate, (2) silicon dioxide (including hydrate, silica, quartz, etc.);
■Alumina.

(2) Silicates containing 30% by weight or more of 5iQ2 (for example, amorphous or crystalline clay minerals, aluminosilicate compounds (including calcined products and hydrates), and hot asbestos.

zircon, fly ash, etc.), ■)l(], ln,
2r.

and oxides of [i, ■ sulfates of Ca and Ba, ■
+-1, Na, and Ca phosphates (including monohydrogen salts and dihydrogen salts), ■ cr, na, and K benzoates, ■ Ca, Ba, ln, and Mn terephthalates, q()))Ig, Ca, Ba, Zn,
Cd, Pb, Sr, In, f'
c, Co, 13 and old titanate, □Ba,
and Pb chromate, @carbon (e.g. carbon black, graphite, etc.), ■glass (e.g. glass powder,
glass peas, etc.), [phase] bolt (l C03, ■ button 11
Stone, and [strain] ln3 are exemplified. Particularly preferred are calcium carbonate, anhydrous silicic acid, hydrated silicic acid, aluminum oxide, aluminum silicate (including calcined products, hydrates, etc.), monolithium phosphate, trilithium phosphate, putrium phosphate, IM calcium, Barium chloride.

Titanium oxide, lithium benzoate, double salts of these compounds (including hydrates), glass powder, clay (including kaolin, bentonite, clay, etc.), talc.

Examples include diatomaceous earth.

In addition, the internally generated particles (B) are polyester 'IAJJA
It is produced and precipitated from catalyst residues and the like and incorporated into the polymer, and a conventionally known method for forming internally precipitated particles can be used for this dispersion. For example, JP-A-48-61556, JP-A-51-11
No. 2860, JP-A-51-115803.

JP-A-53-41355, JP-A-54-9039
The method disclosed in Publication No. 7 and the like can be used. It is preferable that the internally precipitated particles are formed between the stage when the heptamer production reaction is substantially completed and the initial stage of the polycondensation reaction. Preferable examples of the catalyst used in the heptamer production reaction and the compounds added in this reaction step include calcium compounds and lithium compounds. Furthermore, as a component that forms this calcium compound or lithium compound, for example, acetic acid.

Aliphatic carbonic acids such as propylene A') acid, acetic acid, etc.; benzoic acid, p-methylbenzoic acid, naphthoate, etc.
'Group 4 carboxylic acid; meblu alcohol, edial]
Alcohols such as alcohol, propyl alcohol, butyl alcohol, etc.; ethylene glycol.

Glycols such as pyrene glycol; chlorine.

Examples include hydrogen. To explain further, the lithium compound includes - a salt of the above-mentioned aliphatic carboxylic acid;
Salts of aromatic carboxylic acids, Alcola-1~.

Examples include glycolate, chloride, and hydride. The formation of internally precipitated particles is usually carried out by adding a phosphorus compound to a system in which the above-mentioned compounds are present. Examples of phosphorus compounds include phosphoric acid.

phosphorous acid, their esters (e.g. furkyl esters,
aryl esters, etc.). Also,
Other additives (for example, lithium phosphate, etc.) can be used to improve the particle size, stabilization, etc. of internally precipitated particles.

Among the internally precipitated particles, those containing calcium, lithium cum J) and phosphorus have a relatively large particle size, and those containing lithium and phosphorus have a relatively small particle size, so the composition is changed depending on the desired particle size. be able to. Preferred internally precipitated particles include lithium element 0.03~
Mention may be made of particles containing 5% by weight of elemental calcium, 0.03-5% by weight of elemental calcium and 0.03-10ii% of elemental phosphorus.

The internally precipitated particles can be separated from the polymer by, for example, the method described below, and their particle size, amount, etc. can be determined.

Particle Separation Method] Polyester or polynisder film is sufficiently washed with methanol to remove surface deposits, washed with water, and dried.

Collect 500 g of the film, add 0-chlorophenol 4.5K () to it, raise the temperature to 100°C while stirring, and after raising the temperature, leave it as it is for another 1 hour to dissolve the polyester part. If the polyester portion does not dissolve, such as when it is crystallized, the above-mentioned dissolution operation is performed after melting the polyester portion and rapidly cooling it.

Next, in order to remove coarse insoluble matter other than internal particles such as dust contained in the polyester or reinforcing agent added, the dissolved solution is filtered using a C-1 glass filter, and the weight is subtracted from the sample weight.

Separation ultracentrifuge 40P type []-tar RP3 manufactured by Hitachi, Ltd.
0 and the above glass filter per cell? After injecting 30cc of the solution after each door, the rotor was adjusted to 450Orp.
After confirming that there are no rotational abnormalities, vacuum the rotor and increase the rotation speed to 3ooooorpm.
Particles are centrifuged at this rotation speed.

Separation is completed after approximately 40 minutes, and this can be confirmed, if necessary, by checking that the light transmittance of the liquid after separation at 375 mμ becomes a constant value that is higher than that before separation. After separation, the supernatant liquid is removed by decanting to obtain separated particles.

Separated particles may be contaminated with polynisdale components due to insufficient separation, so the collected particles may be heated to 0 at room temperature.
- After adding chlorophenol and suspending it almost uniformly, perform ultracentrifugation again. This operation, which will be described later, must be repeated until a melting peak corresponding to the polymer can no longer be detected by performing scanning differential calorimetry on the core particles after drying the particles.

Finally, the separated particles thus obtained were heated to 120°C.

Vacuum dry for 16 hours and weigh.

Note that the separated particles obtained by the above operation contain both internally precipitated particles and spherical porous silica particles.

For this reason, it is necessary to determine the amount of internal particles and the amount of spherical porous silica particles separately. First, the separated particles are quantitatively analyzed for metal content to determine the content of Ca and Li.

Calculate the content of metals other than Ca and Li. Next, the separated particles are heated under reflux for 6 hours or more in 3 times the molar amount of ethylene glycol, and then the ethylene glycol is distilled off to achieve a temperature of 200° C. or higher for depolymerization, so that only the internal particles are dissolved. The separated particles obtained by centrifuging the remaining particles are dried and weighed to determine the amount of external particles, and the difference from the initial total amount of separated particles is taken as the internal precipitated particle type.

Note that the internally precipitated particles may contain trace amounts of other metal components such as zinc, manganese, magnesium, cobalt, or anti-E, germanium, titanium, etc., within a range that does not impede the effects of the present invention. Good too.

In the present invention, particles having the same composition as the internally precipitated particles can be separately produced and added to the aromatic polyester. These particles can be called externally added precipitated particles (C), and can be used in combination with the spherical porous silica fine particles.

The particle size, density, etc. of the particles in the polymer can be determined in the same manner as for internally precipitated particles.

The average particle size of the inert fine particles (3) is in the range of 0.01 to 4 μm, preferably in the range of 0.05 to 3 μm,
Particularly preferably, the thickness is in the range of 0.1 to 2 μm.

In the present invention, when the spherical porous silica fine particles (2) and the inert fine particles (3) are used, the content of the spherical porous silica fine particles is 0 with respect to the aromatic polyester (1).
．． 005 to 4 m%, preferably 0.01 to 12 m%
, more preferably 0.04 to 1% by weight, particularly preferably 0.1 to 0.5% by weight. On the other hand, inert fine particles (3
) content is 0.005 to 4 for aromatic polyester
% by weight, preferably 0.01-2% by weight, more preferably 0.01-1% by weight, particularly preferably 0.05-0.
It is 5%.

If the content of spherical porous 1 silica particles or inert particles is too small, the synergistic effect of using two types of particles, large and small, will be reduced.
This is not preferable because properties such as runnability, wear resistance, fatigue resistance, crushability, and end surface alignment deteriorate. on the other hand,
Contains spherical porous silica particles or inert particles m
If the amount is too large, the surface of the film becomes too rough and, for example, the electromagnetic conversion characteristics of a magnetic tape are deteriorated, which is not preferable.

When producing the biaxially oriented film of the present invention, in order to intimately mix spherical porous silica particles or inert particles thereof with aromatic polyester, these particles are
The aromatic polyester may be thoroughly kneaded with the aromatic polyester in a polymerization pot before or during polymerization, in an extruder when pelletizing after polymerization, or in an extruder when melt extruding into a sheet. .

The polyester film of the present invention has, for example, a melting point (Tm
:'C) Or melt-extrude aromatic polyester at a temperature of Tm+70>'C to obtain an intrinsic viscosity of 0.35 to 0.9/
(TIJ-10) to (1 g)
+70) Stretched at a temperature of 2.5 to 5.0 times at a temperature of 'C (where ■g: aromatic polystyrene stylus transition temperature), and then the first stage of stretching was carried out in a direction perpendicular to the above stretching direction. direction, the second stage stretching will be in the horizontal direction) (Kochō (
J(°C) ~ (1g+70)'C at a temperature of 2.5~5.
It can be manufactured by stretching at a magnification of 0x. In this case, the area stretching ratio is preferably 9 to 22 times, more preferably 12 to 22 times. The stretching means was 4-biaxial stretching.

Either sequential biaxial stretching may be used.

Furthermore, the biaxially oriented film has (1g+70>'C~
It can be heat-set at a temperature of 1000 m (°C). For example, 190 for polyethylene terephthalate film
It is preferable to heat set at ~230°C. The heat setting time is, for example, 1 to 60 seconds.

The thickness of the polynisder film is preferably 1 to 100 μm, more preferably 1 to 50 μm, and especially 1 to 25 μm.

The polyester film of the present invention has a small coefficient of friction during running and has very good operability. Furthermore, when this film is used as a base for a magnetic tape, the base film is hardly scratched due to contact with the running part of a magnetic recording/reproducing device (hardware) and has good durability.

By combining the above-mentioned advantages as a film product and advantages during film formation, the film of the present invention particularly has the following advantages:
As a base film for high-grade magnetic applications (
*It is extremely useful and has the advantage of being easy and stable to manufacture. The polyester film of the present invention can be used for high-grade magnetic recording media such as micro-recording materials, compact or high-density floppy disk products, etc.
Ultra-thin material for long-term recording of audio and video, etc.

It is suitable as a base film for high-density recording magnetic films, magnetic recording films for high-quality image recording and reproduction, such as metals, vapor-deposited magnetic recording materials, and the like.

Therefore, according to the present invention, there is also provided a magnetic recording medium in which a magnetic layer is provided on one or both sides of the biaxially oriented polyester film of the present invention.

The method of providing the magnetic layer 11 and the magnetic t' layer on the base film is known per se, and the known magnetic layer and method of providing the same can be employed in the present invention.

The 21lqh oriented polyester film of the present invention can be used for various purposes in addition to the above-mentioned magnetic recording media. For example, it is useful for uses such as capacitors, packaging, and vapor deposition.

In addition, various physical property values and characteristics provided in the present invention were measured and determined as follows.

(1) Particle size of spherical porous silica particles There are the following conditions for particle size measurement.

1) When calculating the average particle size 1 particle size ratio etc. from powder 2) When calculating the average particle size 2 particle size ratio etc. of particles in a film 1) From powder: Electron microscope sample stage - [N] Scatter the powder so that individual particles do not overlap as much as possible, form a thin gold film deposited layer (200 to 300 layers thick) on the surface using a gold sputtering device, and magnify 10,000 to 30,000 times using a scanning electron microscope. Observe at a magnification of
) 500, the maximum diameter of at least 100 particles (D
li), minimum diameter (Dsi) and area circular diameter (Di)
seek. The maximum diameter (old), minimum diameter (Ds), and average particle diameter (T5) of the particles are expressed by the number average values expressed by the following equations.

Old = (Σ　Dli)/n.

i=1 Ds=(ΣDSi)/n.

i=1 D-(Σ Di>/n 1=1 2) For particles in a film: A small piece of sample film was fixed on a scanning electron microscope sample stage and sputtered using a JEOL sputtering device (JFC-110).
The surface of the film is subjected to ion etching treatment using a Type 0 ion sputtering device) under the following conditions. condition is,
Install test gear 31 in the perger, about 10-31orr
The degree of vacuum was increased to a vacuum state of 1, and ion etching was performed for about 10 minutes at a voltage of 0.25 kV and a current of 12.5 mA.

Furthermore, using the same equipment, gold spacks are applied to the film surface.
Observe with a scanning electron microscope at 10,000 to 30,000 times.
Maximum diameter of at least 100 particles at 00 (Dli)
, @ Find the small diameter (Dsi) and the area circular diameter (old). The following steps are carried out in the same manner as in 1) above.

(2) Particle size etc. of particles other than spherical porous wrinkle force fine particles 1)
Average particle size: CP-50 type Centrifugal Particle V analyzer (Centrifugal Particle 5iz
The particle size corresponding to 50 mass percent is read from the integrated curve of particles of each particle size and their abundance, which is calculated based on the obtained centrifugal sedimentation curve. Average particle size (BOOkf particle size measurement technique) published by Nikkan Kogyo Shimbun.

1975, 2, pp. 242-247).

2) Particle size ratio A small piece of the film is fixed and molded with epoxy resin, and an ultra-thin section (cut parallel to the film flow direction) with a thickness of approximately 600 mm is created using a microtome. The cross-sectional shape of the lubricant in the film was observed using a transmission electron microscope (manufactured by Hitachi, Ltd., model 1-800), and was expressed as the ratio of the maximum diameter to the minimum diameter of the lubricant.

3) Relative standard deviation 1) Calculate the integrated curve J: ri difference particle size valve A5, and calculate the relative standard deviation based on the following definition formula of relative standard deviation.

Relative standard deviation - Here, or: Each particle diameter (μm) determined in section i): Average diameter (μm) determined in section 1) n: Minute when calculating the integrated curve in section 1) υ1 Number φi: represents the existence probability (masparen l-) of each particle size particle.

(3) Determine the particle surface area BET by applying the adsorption theory. A constant pressure volume gravimetric method is adopted as the measurement method, N2 is used as the adsorption gas, and the measurement temperature is set to -195°C using a liquid nitrogen bath.

BET formula % formula % However, PS: Nitrogen saturated vapor pressure at measurement temperature P: Nitrogen pressure at adsorption equilibrium V: Adsorption amount at adsorption equilibrium Vm: Monomolecular layer adsorption amount: Constant.

Draw a graph of the relationship between □ and - using P P , draw a straight line with - in the range of 0.05 to 0.35, and calculate Vm and K from its intercept and slope. calculate. In this case, the area occupied by nitrogen molecules is 16.2 people.

(4) Film surface roughness (Ra) This is the value defined in JIS-BO601 as the center line average roughness (Ra), and in the present invention 5E-30C
). The measurement conditions are as follows.

(a) Stylus tip radius: 2μm (b) Measuring pressure: 30mg (C) Cutoff: 0.25mm (d) Measuring length: 2.5mm (e) How to summarize the data - Repeatedly measure the data 5 times. , the largest value is 1
41 after the decimal point of the average value of the remaining 4 data
'j F] is rounded off and displayed to the third decimal place.

(5) 17 ring coefficient (μk) of the film In an environment of temperature 20°C2 humidity 60%, cut the film to iJl/2 inch using a fixing rod (surface roughness 0.3 μm).
angle θ-(152/180)π radians (152°)
to avoid movement (friction) at a speed of 200 cm per minute. The exit tension (T2: g) when the entry tension is 1-1 or 35g is detected by the exit tension detector after the film has traveled 90m when the tension controller is adjusted, and the running friction coefficient μk is calculated using the following formula. Calculate.

μk − (2,303/ θ ) log (d2/
Ding1)-〇、86810!11 (T2/35)(
6) Scrapability The scratchability of the running surface of the film was evaluated using a 5-stage mini super calendar. The calender is a 5-stage calender consisting of an iron roll and a sudir.The processing temperature is 80'C, and the linear pressure applied to the film is 200K (1/
Cm, the film speed was 501 n/min, and the running film was run for a total length of 2000 m, and the abrasion resistance of the film was evaluated based on dirt adhering to the top roller of the calendar.

Five-step evaluation: ◎ No stains on the nylon roll Q Almost no stains on the nylon roll △ Slight stain on the nylon roll 1f1 measured at 35°C using phenol as a solvent, the unit is 100 CC/(].

<Example> The present invention will be explained below with reference to Examples.

Comparative Example 1 Dimable terephthalate and ethylene glycol were mixed with manganese acetate (ester exchange catalyst), antimony trioxide (polymerization catalyst), phosphorous acid (stabilizer) and average particle size of 0.56μ
In the presence of kaolin (lubricant) having an m2 particle size ratio of 10, polymerization was carried out by a conventional method to obtain polyethylene terephthalate having an intrinsic viscosity of 0.62.

This polyethylene terephthalate pellet was
℃, after drying for 3 hours, the molten polymer was fed to an extruder hopper and melted at a melting temperature of 280 to 300℃.
Extrude through a slit-shaped die with a surface finish of about 0.3S to a rotary cooling drum with a surface temperature of 20°C, and
00 μm unstretched film (77).

The unstretched film thus prepared (7) was preheated at 75°C, and heated with one IR heater at a surface temperature of 900°C from 15 mm above while rolling at low and high speeds. It was longitudinally stretched 3.5 times by a difference in the surface speed of high-speed rolls, rapidly cooled, and then fed to a stenter and stretched 3.7 times in the transverse direction at 105°C. The obtained biaxially stretched film was heat set at a temperature of 205°C for 5 seconds to obtain a biaxially oriented film with a thickness of 15 μm.

(Although the QRadar film had good abrasion resistance, it had a large running friction coefficient and was unsatisfactory.

The properties of this film are shown in Table 1.

Comparative Example 2 Instead of kaolin, average particle size 0.72 μm2 particle size ratio 1.4
A biaxially oriented film with a thickness of 15 μm was obtained in the same manner as in Comparative Example 1 except that calcium carbonate was used. Although this film had good running properties, white powder was generated in the calender culm. The properties of this film are shown in Table 1.

Comparative Examples 3 and 4 Instead of kaolin, average particle size 0.65 μm 1 particle size ratio 10
of porous silica (Comparative Example 3), or average particle size of 0.35
One strand of biaxially oriented film with a thickness of 15 μm was prepared in the same manner as in Comparative Example 1 except that calcium carbonate (Comparative Example 4) having a μm2 particle size ratio of 1.4 was used.

Although the material of Comparative Example 3 had good machinability, it had a large running friction coefficient and was unsatisfactory. The surface of Comparative Example 4 was flat, but the running properties were poor and white powder was generated, making it unsatisfactory. These properties are not shown in Table 1.

Examples 1 to 3 Biaxially oriented films with a thickness of 15 μm were obtained in the same manner as in Comparative Example 1, except that spherical porous silica listed in Table 1 was used instead of kaolin. All films had a flat surface and excellent running properties, and were satisfactory with few scratches and white powder generation.

These properties are shown in Table 1.

Comparative Example 5 A biaxially oriented film with a thickness of 15 μm was prepared in the same manner as in Comparative Example 1, except that spherical porous silica listed in Table 1 was used instead of kaolin. This film had good running properties because the particle size of the spherical porous silica was too large, but the surface was rough and the amount of white powder generated was unsatisfactory. These properties are shown in Table 1.

Comparative Examples 6 to 8 Biaxially oriented films with a thickness of 15 μm were obtained in the same manner as in Comparative Example 1, except that fine particles listed in Table 2 were used instead of kaolin.

In Comparative Examples 6 to 8, since the films of Comparative Examples 1 to 4 were unsatisfactory, the abrasion resistance was improved by adding calcium carbonate with a small particle size together with kaolin or porous silica with a large particle size. However, the improvement effect was small and unsatisfactory. These properties are shown in Table 2.

Examples 4 to 6 Biaxially oriented polyester films with a thickness of 15 μm were obtained in the same manner as in Comparative Example 6 except that the fine particles shown in Table 2 were used. Since these films used spherical porous silica as small particles, the running resistance was low, and the generation of white powder was extremely low, which was satisfactory. These characteristics are the second
Shown in the table.

Example 7 A mixture of dimethyl terephthalate and ethylene glycol, manganese acetate as a transesterification catalyst, rhidium acetate and calcium acetate dissolved in ethylene glycol, and spherical porous material with an average particle size of 0.54 μm uniformly dispersed in ethylene glycol. Silica 0.05% by weight
(to polyester) and carry out a transesterification reaction using a conventional method. When the transesterification reaction is completed, trimethyl phosphate and antimony trioxide are added as a catalyst, and the intrinsic viscosity (0-
Polyethylene terephthalate (chlorophenol, 35° C.) of 0.62 was obtained.

When the internally precipitated particles m in this polyethylene terephthalate were determined by the particle separation method described in (a) above, it was found that the internally precipitated particles corresponded to the particles of spherical silica added as externally added particles. In addition, when the polyethylene terephthalate was sandwiched between prepared slides, melted, and cooled, it was observed under a microscope.
It was found that a large number of particles with an average particle size of 0.7 μm and spherical particles with an average particle size of 0.54 μm were mixed together. The former are internal precipitated particles precipitated in the polymer during polyester production, and the latter are spherical porous silica particles added from the outside.

Next, the polyethylene terephthalate was heated to 280 to 30
Melt extrusion from a slit at 0°C, quenching, stretching and heat setting of the unstretched film at a longitudinal stretch ratio of 3.5 times, a transverse stretch ratio of 3.7 times, and a heat treatment temperature of 205°C, resulting in a thickness of 1
A biaxially oriented film of 5 μm was obtained.

The properties of this film are shown in Table 2.

(The film obtained under the above conditions had a small amount of white powder, and had excellent runnability and was satisfactory.

Claims (1)

[Claims] 1. (1) an aromatic polyester, and (2) (a) a particle size ratio defined by the ratio of maximum diameter to minimum diameter of 1.0 to 1.2, and (b) The average particle size is 0.01 to 4 μm, and (c)
A biaxially oriented polyester film obtained by molding an intimate mixture consisting of 0.005 to 4% by weight (based on aromatic polyester) of spherical porous silica fine particles having a specific surface area of 70 m^2/g or more by the BET method. 2. Spherical porous silica particles are zeolite (Na_2O・2SiO_2・Al_2O_3・nH_
2. A film according to claim 1 prepared from acid treatment of 2O). 3. Claim 1, wherein the relative standard deviation of the spherical porous silica particles represented by the following formula (A) is 0.5 or less
The film described in section. Relative standard deviation = ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) Here, Di: Area circle equivalent diameter of individual particles (μm) @D@: Average value of area circle equivalent diameter (=▲ There are mathematical formulas, chemical formulas, tables, etc. ▼) n: Represents the number of particles. 4, (1) aromatic polyester, (2) (a) particle size ratio defined by the ratio of maximum diameter to minimum diameter is 1.0 to 1.2, (b) average particle size is 0.01 ~4μm, and (c)
0.005 to 4% by weight (based on aromatic polyester) of spherical porous silica fine particles having a specific surface area of 70 m^2/g or more by the BET method, and (3) non-porous particles having an average particle size of 0.01 to 4 μm. Active particles 0
．． Biaxially oriented polyester film obtained by molding an intimate mixture of 0.005 to 4% by weight (based on aromatic polyester).