JP3043584B2 - Polyester composition and polyester film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester composition and a polyester film in which specific silicone resin fine particles are dispersed and contained, and more particularly, to a method in which specific silicone resin fine particles are well dispersed in polyester and excellent in film forming property. The present invention relates to a polyester composition and a biaxially oriented polyester film using the composition, which is excellent in flatness, slipperiness and abrasion resistance.

[0002]

2. Description of the Related Art Biaxially oriented polyester films represented by polyethylene terephthalate films have been used for various purposes, particularly for magnetic recording media, because of their excellent physical and chemical properties.

[0003] In a biaxially oriented polyester film, its slipperiness and abrasion resistance are major factors that affect the workability of the film manufacturing and processing steps and the product quality. If these are insufficient, for example, when a magnetic layer is applied to the surface of a biaxially oriented polyester film and used as a magnetic tape, friction and wear between the coating roll and the film surface are severe, and wrinkles and scratches on the film surface are likely to occur. Also, when used for VTRs and data cartridges, friction occurs between many guides, reproducing heads, etc. during pulling out, winding up, and other operations from cassettes and the like, causing scratches, distortion, and even base film. The occurrence of white powder due to surface shaving or the like often causes dropout.

Many studies have been made on such problems, and among them, the method of adding fine particles of silicone resin (for example, Japanese Patent Application Laid-Open No. Sho 62-172131) has a large improvement effect, and is expected to develop as a technology in the future. You.

However, the following phenomenon is pointed out as a problem in the film containing the silicone resin fine particles in addition to the physical properties of the film at the time of film formation.

That is, when a film containing the silicone resin fine particles is formed into a film, when a molten polymer is extruded from a slit die onto a rotating cooling drum, an electrostatic application method is usually used to improve sticking to the drum. The film forming method used is adopted.
As a result, a current drop or a discharge spark occurs, and the sticking effect is reduced, so that the electrostatic wire must be replaced in a short time.

[0007] Such a phenomenon becomes remarkable with an increase in the amount of the silicone resin particles added, so that the problem is small in high-grade applications such as a film for a metal video tape to which a relatively small amount is added, but under relatively severe conditions. It is necessary to increase the amount of addition in order to run the film, and this is a problem in a film for a regular video tape which requires even higher productivity, and the solution of this problem is awaited.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have developed a silicone resin capable of stably satisfying both the slipperiness and the abrasion resistance of such a film and capable of greatly reducing electrostatic wire contamination. As a result of intensive studies to develop fine particles, silicone resin fine particles having a small amount of silanol groups (Si-OH bonds) as terminal groups and having a surface carbon element present in a certain amount or more relative to silicon are converted to polyester. The present inventors have found that the inclusion of satisfactorily in the present invention satisfies the slipperiness and the abrasion resistance and that the contamination of the electrostatic wire can be greatly reduced.

[0009]

That is, according to the present invention, 80% by weight or more of particles are composed of a bonding unit represented by the following formula, and the silanol group (Si-OH bond) determined by infrared spectroscopy is used. -O-Si bond relative absorption intensity (I
_(Si-OH / I _Si-O-Si ) is 0.05 or less and the surface atomic ratio of carbon to silicon (C / Si) determined by photoelectron spectroscopy
Is 0.9 or more, and silicone resin fine particles having an average particle size of 0.05 to 3 μm are added to the polyester in an amount of 0.0
It is a polyester composition characterized by containing from 0.5 to 5% by weight.

[0010]

## STR2 ## RSiO _3/2 (wherein, R is one at least selected from the group consisting of alkyl groups and phenyl groups having 1 to 6 carbon atoms.)

The 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, especially film forming by melt molding.
As the aromatic dicarboxylic acid, for example, terephthalic acid,
Examples thereof include 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenoxyethane dicarboxylic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, and anthracene dicarboxylic acid. Examples of the aliphatic glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol,
Examples thereof include polymethylene glycol having 2 to 10 carbon atoms such as decamethylene glycol and alicyclic diols such as cyclohexanedimethanol.

In the present invention, polyesters containing alkylene terephthalate and / or alkylene naphthalate as a main component are preferably used.

[0013] Among such polyesters, in particular, polyethylene terephthalate and polyethylene-2,6-naphthalate, for example, terephthalic acid and / or 2,6-naphthalenedicarboxylic acid account for at least 80 mol% of all dicarboxylic acid components, A copolymer in which 80% by mole or more of all glycol components is ethylene glycol is preferred. At that time, 20 mol% or less of the total acid component can be the above-mentioned aromatic dicarboxylic acids other than terephthalic acid and / or 2,6-naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid. And alicyclic dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid. Further, 20 mol% or less of the total glycol component can be the above-mentioned glycol other than ethylene glycol. For example, aromatic diols such as hydroquinone, resorcinol, 2,2-bis (4-hydroxyphenyl) propane, Aliphatic diols having an aromatic ring such as 4-dihydroxydimethylbenzene, and polyalkylene glycols (polyoxyalkylene glycols) such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol can also be used.

The polyester of the present invention includes:
For example, aromatic oxyacids such as hydroxybenzoic acid, ω-
Also included are those which copolymerize or combine a component derived from an oxycarboxylic acid such as an aliphatic oxyacid such as hydroxycaproic acid at 20 mol% or less based on the total amount of the dicarboxylic acid component and the oxycarboxylic acid component.

In the present invention, the fine particles of the silicone resin contained in the polyester are represented by the following formula:

[0016]

A crosslinked silicone resin having a bonding unit represented by RSiO _3/2 (where R is at least one selected from an alkyl group having 1 to 6 carbon atoms and a phenyl group) in an amount of 80% by weight or more. Particles.

The above-mentioned bonding unit has the following structural formula.

[0018]

Embedded image

Here, R is the same as above.

The method for producing the silicone resin fine particles is known in the art. For example, a method of hydrolyzing and condensing an organotrialkoxysilane (for example, Japanese Patent Publication No. 40-16917 or Japanese Patent Publication No. 2-22767) or starting with methyltrichlorosilane Method for producing polymethylsilsesquioxane fine particles as a raw material (for example, Belgian Patent 57241
No. 2). However, in the present invention, the production method is not limited as long as the particles have the characteristics described below, and silicone resin fine particles produced by any method may be used.

R in the above formulas [Chemical Formulas 1 to 3] and the structural formula [Chemical Formula 4] is at least one selected from an alkyl group having 1 to 6 carbon atoms and a phenyl group. Examples thereof include an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. These can be one or more. When R is a plurality of groups, for example, when it is a methyl group and an ethyl group, it can be obtained by producing a mixture of methyltrimethoxysilane and ethyltrimethoxysilane as a starting material. However, in consideration of the production cost and the ease of the synthesis method, silicone resin (polymethylsilsesquioxane) fine particles in which R is a methyl group are preferable.

The silicone resin particles preferably have a substantially spherical shape, and are particularly effective for imparting slipperiness.

In the present invention, the content of the silanol group (Si—OH bond) in the silicone resin fine particles must be less than a certain content with respect to the Si—O—Si bond which is the skeleton of the bonding unit of the silicone resin fine particles. In addition, it is necessary that the silicone resin fine particles satisfy both of two physical properties in which the ratio of the carbon element constituting the organic group to the silicon element among the elements constituting the surface is at least a certain ratio.

That is, in the present invention, the silanol groups in the silicone resin fine particles are converted to Si—OH by infrared spectroscopy.
The absorption intensity (I _Si-OH ) having a peak near 900 cm ⁻¹ belonging to Si—O—Si belongs to 1000 to 1
It is necessary that the relative absorption intensity with respect to the absorption intensity (I _Si-O-Si ) having a peak around 100 cm ^-1 is 0.05 or less. When a film is formed using a polyester composition containing silicone resin fine particles having a relative absorption strength exceeding 0.05, the contamination of the electrostatic wire is significantly deteriorated, and it is necessary to frequently replace the electrostatic wire. Absent. Such silicone resin fine particles having a relative absorption strength of 0.05 or less can be obtained by devising synthesis conditions at the time of production, or by subjecting commercially available silicone resin fine particles exceeding 0.05 to heat treatment, a condensation reaction between silanol groups can be achieved. Can be obtained by reducing the silanol group, and furthermore, the silanol group can be reduced by adding a silane coupling agent and reacting to reduce the relative absorption intensity to 0.05 or less. In the present invention, silicone fine particles obtained by any method may be used.

Further, in the present invention, carbon which is a constituent element of an organic group on the surface of the silicone resin fine particles,
In the measurement by photoelectron spectroscopy, the atomic ratio (C / Si) to the silicon element, which is the skeleton element of the silicone resin fine particles, needs to be 0.9 or more. This atomic ratio (C /
If Si) is less than 0.9, it is not preferable because the film cannot sufficiently satisfy the slipperiness and abrasion resistance of the film, which are characteristics of the organic particles. The silicone resin fine particles having an atomic ratio (C / Si) of less than 0.9 include, for example, when R is a methyl group, that is, when polymethylsilsesquioxane fine particles have a high content of surface silanol groups or a methyl group. Silicone fine particles with a low content are applicable examples.

The average particle size of the silicone resin fine particles in the present invention is 0.05 to 3 μm, preferably 0.3 to 3 μm.
2.0 μm. When the average particle diameter is less than 0.05 μm, it is difficult to obtain the effect of improving the slipperiness and the abrasion resistance.
If it exceeds m, it is difficult to obtain surface flatness of the film, which is not preferable. Further, it is preferable that the silicone resin fine particles have a spherical particle shape, which is particularly effective for imparting slipperiness.

The addition amount of the silicone resin fine particles in the present invention is 0.05 to 5% by weight based on the weight of the polyester. If the addition amount is too small, the slipperiness of the film deteriorates, while if the addition amount is too large, problems such as insufficient dispersibility in the polymer arise.

In the present invention, the polyester composition may contain the silicone resin fine particles alone, but depending on the use and physical properties of the film, a combination with other fine particles, ie, other organic fine particles and / or inert inorganic particles. May be contained. Other organic fine particles include crosslinked polystyrene fine particles, crosslinked acrylic resin fine particles, melamine resin fine particles, and the like, and the inert inorganic fine particles include aluminum oxide, titanium oxide, silicon oxide, zirconium oxide,
Examples thereof include calcium carbonate, kaolin, clay, and carbon black. The aluminum oxide can take various forms as a crystal form,
α-type, γ-type, δ-type, θ-type, and κ-type aluminum oxides are preferable, and γ-type, δ-type, and θ-type aluminum oxides are particularly preferable.

The other fine particles used in combination with the silicone resin fine particles preferably have an average particle size of 0.05 to 2 μm. The combined amount is based on the weight of the polyester.
Preferably it is 0.01 to 2% by weight.

In the present invention, the timing at which the silicone resin fine particles are dispersed and contained in the polyester may be arbitrarily determined. In the polyester production process, for example, an esterification step of a direct polymerization method using terephthalic acid or 2,6-naphthalenedicarboxylic acid as a raw material, Alternatively, a transesterification step of a transesterification method using dimethyl terephthalate or dimethyl-2,6-naphthalenedicarboxylate as a raw material is preferable, and when the polyester composition containing no fine particles is remelted, the powder of the fine particles is directly used. It may be added to form a polyester composition, or a method in which the fine particles are directly added as a powder when a film is produced using polyester may be used. However, as the timing of adding the fine particles becomes late, it is necessary to take measures such as increasing the kneading share of the melt extruder in order to secure the dispersibility of the fine particles in the film.

In producing a film using the polyester composition of the present invention, a conventionally known method can be applied. For example, the polyester composition can be manufactured by melt extrusion, quenching to obtain an unstretched film, and then stretching the unstretched film biaxially, heat setting, and, if necessary, relaxation heat treatment. At this time, properties such as surface characteristics, density, and heat shrinkage of the film vary depending on stretching conditions and other manufacturing conditions, and are appropriately selected as needed.

For example, the unstretched film is placed in a uniaxial direction (longitudinal direction or lateral direction) from [Tg-10] to [Tg + 6].
0] ° C. (however, Tg: glass transition temperature of polyester) at a stretching ratio of 2.5 times or more, preferably 3 times or more, and then Tg to [Tg] in a direction perpendicular to the stretching direction.
It is preferable that the film is stretched at a temperature of +70] ° C. at a magnification of 2.5 times or more, preferably 3 times or more. Further, if necessary, the film may be stretched again in the machine direction and / or the cross direction. Thus, the total stretching ratio is preferably 9 times or more, more preferably 12 to 35 times, and more preferably 15 to 15 times, as the area stretching ratio.
25 times is particularly preferred. Furthermore, the biaxially stretched film can be heat-set at a temperature of [Tg + 70] ° C to [Tm-10] ° C (where Tm is the melting point of the polyester), for example, at a temperature of 180 to 250 ° C. Is preferred. The heat setting time is preferably 1 to 60 seconds.

In the present invention, the polyester film may be a single-layer film, but may be a laminated film having two or more layers in some cases. In this case, the film layer made of the polyester composition constitutes at least one of the outermost layers. The thickness of this film layer is preferably 0.3 μm or more.

The (total) thickness of the polyester film, whether it is a single-layer film or a laminated film, is preferably 4 to 25 μm, more preferably 5 to 20 μm.

The polyester film of the present invention is excellent in stable slipperiness and abrasion resistance, and is effective for stable productivity during film formation, and is particularly useful as a base film of a magnetic recording medium.

[0036]

The present invention will be described below in detail with reference to examples. Also,
Various physical properties and properties in the present invention were measured and defined as follows.

(1) Measurement of Silanol Group by Infrared Spectroscopy PERKIN ELMER9 manufactured by Perkin Elmer, USA
Infrared analysis was carried out by 83 IR SPECTRO-METER by KBr method which is known as a usual method, and from the obtained IR chart, 900c belonging to Si-OH was obtained.
The absorption intensity (I _Si-OH ) having a peak near m ^-1 is Si-
It is expressed as a relative absorption intensity (Equation 1) with an absorption intensity (I _Si-O-Si ) having a peak around 1000 to 1100 cm ^-1 belonging to _O-Si . (Literature on imputed absorption peak: "Infrared absorption and Raman effect" Kyoritsu Zensho (1958)
Such)

[0038]

(Equation 1)

For each of the absorption intensities, as shown in FIG. 1, the base transmittance T ₀ % and the transmittance T% at the absorption peak are obtained by the following equation (Equation 2).

[0040]

## EQU2 ## I = log (T ₀ / T)

(2) C /
Measurement of Si atomic ratio ESCA LAB manufactured by VG Scientific, UK
Excitation X-rays are measured with a 200 X-ray photoelectron spectrometer using Mg-Kα rays. The powder was measured as a layer having a thickness of 1 mm, and converted from the detection peak areas of the C, O, and Si elements into atomic ratios using the following respective sensitivity coefficients, and further, the surface atomic ratio of carbon and silicon (C / Si) is obtained by calculation.

Sensitivity coefficient of each element: C = 1 O = 2.85 Si = 0.865

(3) Average particle size of particles (d) (i) In the case of calculating average particle size from granules SA-CP4L type centrifugal particle size analyzer (Centrifugal Partic acid) manufactured by Shimadzu Corporation
le Size Analyzer), the particle size corresponding to 50 mass percent was read from the integrated curve of the particle size calculated based on the centrifugal sedimentation curve and the abundance of the particles having the particle size. The average particle size is used.

(Ii) In the case of particles in the film A small piece of the sample film was fixed on a sample stage for a scanning electron microscope, and a sputtering device (JFC-
The film surface is subjected to ion etching under the following conditions using a 1100 type ion etching apparatus). The conditions were as follows: the sample was placed in a bell jar, the degree of vacuum was raised to a vacuum state of about 10 ⁻³ Torr, the voltage was 0.25 kV, and the current was 1
Perform ion etching at 2.5 mA for about 10 minutes. Further, the film surface was subjected to gold sputtering by the same apparatus, and 50,000 to 10,000 by a scanning electron microscope.
Observed at × 2, the equivalent spherical diameter distribution of at least 100 particles is determined by Luzex 500 manufactured by Nippon Regulator Co., Ltd., and calculated from the point of 50% by weight integration.

(4) Coefficient of running friction of film (μk) Measured as follows using the apparatus shown in FIG.
In FIG. 2, 1 is an unwinding reel, 2 is a tension controller, 3, 5, 6, 8, 9 and 11 are free rollers, 4 is a tension detector (entrance), and 7 is a stainless steel SUS304 fixing rod (outside). Diameter 5mmφ, surface roughness Ra =
0.02 μm), 10 is a tension detector (outlet), 1
2 indicates a guide roller, and 13 indicates a take-up reel.

In an environment of a temperature of 20 ° C. and a humidity of 60%, the width 1 /
The film cut into 2 inches is fixed to the fixing rod 7 at an angle θ = (1
52/180) Move (friction) at a speed of 200 cm per minute with contact at π radians (152 °). The outlet tension (T ₂ : g) when the tension controller 2 is adjusted so that the inlet tension T ₁ becomes 35 g is detected by the outlet tension detector after the film has run 90 m, and the running friction coefficient μk is calculated by the following equation. calculate.

[0047]

Equation 3] μk = (2.303 / θ) log (T 2 / T 1) = 0.868log (T 2/35)

(5) Film surface flatness Ra (center line average roughness) is measured according to JIS B0601. Using a stylus-type surface roughness meter (SURFCOM3B) manufactured by Tokyo Seimitsu Co., Ltd., apply a chart (film surface roughness curve) under the conditions of a needle radius of 2 μm and a load of 0.07 g to obtain a film. A portion of the measured length L is extracted from the surface roughness curve in the direction of the center line, and the center line of the extracted portion is set as the X axis, the direction of the vertical magnification is set as the Y axis, and the roughness curve Y = f (x). When expressed, the value (Ra: μm) given by the following equation is defined as the flatness of the film surface.

[0049]

(Equation 4)

In the present invention, eight measurements are made with the reference length set to 0.25 mm, and Ra (μm) is expressed as an average value of five values, excluding three values from the larger value.

(6) Abrasion resistance In the same apparatus as used in FIG. 1 used for measuring the running friction coefficient μk, the winding angle was set to 30 degrees and the inlet tension was set to 50 g at a speed of 300 m / min. Let it. The scraping of the shavings adhering to the fixed bar 7 after running and the scratch of the tape after running are evaluated. At this time, as a fixing rod 7, a 6φmm tape guide (surface roughness Ra = 0.15μ) with insufficient surface finish obtained by bending a SUS sintered plate into a cylindrical shape
m). <Determination of shavings> A: No shavings are observed. ：: Shaved powder is slightly observed. Δ: The presence of shavings can be seen at a glance. X: The shavings are badly adhered.

[Example 1] (1) Production of silicone resin fine particles: 10 with stirring blade
7000 g of an aqueous solution containing 0.2% by weight of sodium hydroxide is placed in a liter glass container, and 1000 g of an aqueous solution is added to the upper layer.
g of methyltrimethoxysilane was gently injected, and after two layers were formed, an interfacial reaction was performed at 10 to 15 ° C. at a rotation speed of 20 rpm for 3 hours, thereby forming particles. Thereafter, the mixture was aged at a temperature of 70 ° C. for 4 hours, cooled, filtered with a reduced pressure filter, and subsequently washed with 3000 g of water to obtain a cake of silicone resin fine particles having a water content of about 50%. Next, K as a silane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd.
2000 g of a 2% aqueous solution of BM603 (N-β (aminoethyl) γ-aminopropyltrimethoxysilane) was poured onto the cake-like material on a filter, and subjected to surface treatment by filtration under reduced pressure. The cake obtained is kept at 90 ° C for 15
The resultant was dried under reduced pressure at rr for 2 hours, and further dried under normal pressure at 150 ° C. for 5 hours to obtain about 400 g of silicone resin fine particle powder.

When the obtained fine particles were observed with an electron microscope, the particle shape was a true sphere, and the particle size distribution obtained by the centrifugal sedimentation method described above showed that 90% or more of the weight was 0.5%.
The average particle size is 0.6 μm with a uniform particle size of ~ 0.7 μm
Of fine particles.

With respect to the fine particles, the relative absorption intensity of the silanol group measured by the infrared spectroscopy described above was 0.0
1. Surface atomic ratio (C / S) measured by photoelectron spectroscopy
i) was 1.2.

(2) Production of polyester composition containing silicone resin fine particles: Using dimethyl terephthalate and ethylene glycol as raw materials, manganese acetate is used as a transesterification catalyst, antimony trioxide is used as a polymerization catalyst, and a stabilizer is used as a stabilizer. Phosphorous acid was added, and at the end of the transesterification reaction, the silicone resin fine particles obtained in (1) were dispersed sufficiently by a conventional method in a 20% by weight ethylene glycol slurry. % By weight, followed by a polymerization reaction, and the intrinsic viscosity (orthochlorophenol,
(35 ° C.) 0.62 polyester (polyethylene terephthalate) composition was obtained. The polyester has a Tg of 70.
° C and Tm of 257 ° C.

(3) Filming the polyester composition:
Pellets of the polyester composition obtained in (2) were mixed with 17
After drying at 0 ° C for 3 hours, the mixture was fed to an extruder hopper and melted at a melting temperature of 280 to 300 ° C.
Then, the mixture was extruded through a slit die having a surface temperature of 30 ° C. onto a rotating cooling drum and rapidly cooled to obtain an unstretched film.

The unstretched film thus obtained was preheated at 75.degree.
m, heated by one IR heater having a surface temperature of 900 ° C. from above, stretched 3.6 times, quenched, then supplied to a stenter, and stretched 3.7 times laterally at 105 ° C. .
The obtained biaxially oriented film was heat-set at a temperature of 205 ° C. for 5 seconds to obtain a heat-set biaxially oriented polyester film having a thickness of 15 μm.

In the production of the unstretched film, the film-shaped molten polymer extruded from the die is
Static electricity was applied by an electrostatic application method in which a voltage of 6 KV was applied to the electrostatic wire, and the electrostatic wire was brought into close contact with the drum. The current flowing through the electrostatic wire immediately after the start of the film production (time 0) and one hour later was measured, and the current reduction rate during this time was determined by the following formula, and the relative evaluation of the electrostatic wire contamination was performed.

[0059]

(Equation 5)

Table 1 shows the characteristics and the current reduction rate of the obtained film.

Comparative Example 1 Example 1 was repeated except that the surface treatment with the silane coupling agent was omitted and the drying under reduced pressure was 90 ° C. and 15 Torr for 4 hours.
Silanol resin fine particles were obtained in the same manner as described above. The relative absorption intensity of silanol groups of the fine particles was 0.14, and the surface atomic ratio (C / Si) was 0.87. Production of the polyester composition containing the fine particles and film formation were all carried out in the same manner as in Example 1. Table 2 shows the results.

Example 2, Comparative Example 2 In Example 2, the surface treatment with the silane coupling agent of Example 1 was carried out except that the concentration of the silane coupling agent during the treatment was 1.0%. It carried out similarly to Example 1. Table 1 shows the results.
Shown in

In Comparative Example 2, the drying conditions during production of the silicone resin fine particles in Example 2 were the same (same as in Example 1).
Example 2 except that the temperature was changed to 4 hours at 90 ° C. and 15 Torr.
Was performed in the same manner as described above. Table 2 shows the results.

Example 3 The same conditions as in Example 1 were used except that the drying conditions in the production of the silicone resin fine particles in Example 1 were 90 ° C. at 15 Torr for 4 hours and 200 ° C. at normal pressure for 10 hours. Carried out. Table 1 shows the results.

[Comparative Example 3] The drying conditions under reduced pressure at the time of producing the silicone resin fine particles of Comparative Example 1 were set at 120 ° C. and 15 Torr.
All were carried out in the same manner as in Comparative Example 1 except that the temperature was strengthened to 10 hours. Table 2 shows the results.

In Examples 1 to 3, the film characteristics were all satisfied and the current reduction rate of the electrostatic wire was as low as 4% or less, which was good, whereas in Comparative Example 1, the relative absorption strength of the silanol group was low. Both surface atomic ratios (C / Si)
Further, in Comparative Examples 2 and 3, any one of them was out of the range of the present invention, so that either one of the film characteristics and / or the current reduction rate of the electrostatic wire was inferior.

Example 4 and Comparative Example 4 In each case, the polyester was changed from polyethylene terephthalate to polyethylene naphthalate.

(1) Production of Silicone Resin Fine Particles: Example 4 was carried out in the same manner as in Example 1, and Comparative Example 4 was carried out in the same manner as Comparative Example 1.

(2) Production of polyester composition and film formation: Both of Example 4 and Comparative Example 4 were carried out in exactly the same manner by the following method.

A polyester (polyethylene naphthalate) was obtained in the same manner as in Example 1 and Comparative Example 4, except that dimethyl 2,6-naphthalenedicarboxylate was used instead of dimethyl terephthalate among the polyester raw materials in Example 1. . The obtained polyester has a Tg of 120 ° C.
m 267 ° C.

Subsequently, the polyester pellets were
After drying at 0 ° C for 3 hours, the mixture was fed to an extruder hopper and melted at a melting temperature of 290 to 310 ° C.
The resulting product was extruded through a slit die having a surface temperature of 60 ° C. onto a rotary cooling drum, and rapidly cooled to obtain an unstretched film.

The unstretched film thus obtained was preheated at 130 ° C., and further cooled between low-speed and high-speed rolls.
mm from above and stretched 3.6 times by heating with one IR heater having a surface temperature of 900 ° C, quenched, and then supplied to a stenter, and stretched 3.7 times in the horizontal direction at 135 ° C. . The obtained biaxially oriented film was heat-set with hot air at 230 ° C. for 5 seconds to obtain a heat-set biaxially oriented polyester film having a thickness of 15 μm.

The relative evaluation of the contamination of the electrostatic wire was performed in the same manner as in Example 1.

The results are shown in Table 3. The results are shown in Table 3.
Although the film characteristics and the rate of current decrease of the electrostatic wire were both good, Comparative Example 4 had a high relative absorption intensity of silanol groups and a small surface atomic ratio (C / Si), and both were within the scope of the present invention. , The current drop rate of the electrostatic wire was large and the film characteristics were poor.

Example 5 Instead of synthesizing silicone resin fine particles, 400 g of a true spherical polymethylsilsesquioxane powder having an average particle diameter of 1.3 μm (trade name: Tospearl 120) manufactured by Toshiba Silicone Co., Ltd. Surface treatment and subsequent steps were performed in the same manner as in Example 1 except that (and 400 g of methanol was added as a dispersing aid) to obtain a polyester (polyethylene terephthalate) composition.

The film is formed by extruding a polyester (polyethylene terephthalate; intrinsic viscosity: 0.62) produced by a conventional method without a lubricant particle in the middle layer, and a polyester composition containing the above silicone resin fine particles in the upper and lower layers, respectively. At 280-300 ° C. by a multi-manifold method to obtain a three-layer laminated unstretched film. The following is carried out in the same manner as in Example 1, and the upper and lower surface layers are each 1.5 μm.
m, a middle layer of 12 μm, and a total thickness of 15 μm were obtained.

Comparative Example 5 A polyester composition was obtained in the same manner as in Example 5, except that the polymethylsilsesquioxane powder used in Example 5 was used without any pretreatment. The following steps were carried out in exactly the same manner as in Example 5.

The results of Example 5 and Comparative Example 5 are shown in Table 4. The results show that Example 5 was excellent in both film characteristics and current reduction rate of the electrostatic wire, whereas the relative absorption strength of the silanol group was good. Comparative Example 5 using fine particles as they are and having a small surface atomic ratio (C / Si), all of which are out of the range of the present invention, shows that the electrostatic wire contamination was 5% in Example 5.
More than twice as high, and the abrasion resistance was poor.

Example 6 A polyester (polyethylene terephthalate: intrinsic viscosity 0.62) containing no lubricant particles produced by a conventional method was subjected to a twin-screw extruder.
The fine particles produced by the same method as the method of producing the silicone fine particles of Example 1 were melt-kneaded and extruded while adding an equivalent amount of 1% by weight to the polyester with a quantitative feeder, and then pelletized to obtain a polyester composition having an intrinsic viscosity of 0.60. I got

Melting temperature: 260-300 ° C. Screw: length 1850 mm (D = 44 mmφ) Screw with kneading function Extrusion speed: 50 kg / Hr (maximum capacity 110 kg / H)
r) In the subsequent film formation, the polyester containing no lubricant particles and the polyester composition containing the silicone resin fine particles obtained by the above method, which were also used in the above-mentioned melt extrusion, were mixed at a concentration of 0.1% by weight of the fine particles. %, And then formed into a film in the same manner as in Example 1.

The obtained results are shown in Table 1. As in Example 1, good results were obtained in both the current reduction rate of the film characteristic electrostatic wire.

[0082]

[Table 1]

[0083]

[Table 2]

[0084]

[Table 3]

[0085]

[Table 4]

[0086]

According to the present invention, it is possible to provide a polyester composition and a polyester film which are less contaminated by an electrostatic wire when formed into a film, and which contain both silicone resin fine particles and are excellent in both slipperiness and abrasion resistance.

[Brief description of the drawings]

FIG. 1 is an infrared spectroscopic analysis chart of silicone resin fine particles.

FIG. 2 is a schematic view of an apparatus for measuring a running friction coefficient (μk).

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 unwinding reel 2 tension controller 4 tension detector (entrance) 7 fixed rod 10 tension detector (exit) 13 take-up reel

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-128394 (JP, A) JP-A-6-192426 (JP, A) JP-A-5-148364 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08J 5/18 CFD C08G 77/00-77/62 C08L 83/00-83/16

Claims (5)

(57) [Claims] 1. At least 80% by weight of particles are composed of a bonding unit represented by the following formula, and the relative absorption intensity (I) of a silanol group (Si—OH bond) with respect to a Si—O—Si bond determined by infrared spectroscopy. _(Si-OH / I _Si-O-Si ) is 0.05 or less and the surface atomic ratio (C / Si) of carbon and silicon determined by photoelectron spectroscopy is 0.9 or more. 05
A polyester composition containing from 0.005 to 5% by weight of silicone resin fine particles of from 3 to 3 μm based on the weight of the polyester. ## STR1 ## RSiO _3/2 (wherein, R is one at least selected from the group consisting of alkyl groups and phenyl groups having 1 to 6 carbon atoms.) 2. The polyester composition according to claim 1, wherein the silicone resin particles are substantially spherical particles of polymethylsilsesquioxane. 3. The polyester composition according to claim 1, wherein the polyester is a polyalkylene terephthalate or a polyalkylene naphthalate. 4. A biaxially oriented polyester film comprising the polyester composition according to claim 1. 5. A biaxially oriented polyester film, wherein the film is a laminated film having two or more layers, at least one of which is made of the polyester composition according to claim 1.