JPH0665483A - Polyester composition and film composed of the composition - Google Patents

Abstract

PURPOSE:To obtain a polyester composition giving a film having excellent flatness, abrasion resistance and scratch resistance and suitable for magnetic tape, photographic film, graphic arts film, etc., by adding acicular inorganic particles to a polyester. CONSTITUTION:The objective composition is produced by compounding (A) a polyester composed of an aromatic dicarboxylic acid as a bifunctional acid component and a glycol component (preferably a polymer containing alkylene terephthalate or alkylene naphthalate as main constituent unit) with (B) preferably 0.01-5wt.% of acicular particles of an inorganic substance (preferably titanium oxide, aluminum oxide or zirconium oxide). The component B is preferably dispersed in glycol, etc., to be used as a raw material for the component A, slurrying the mixture and directly adding the slurry to the polymerization reactional system or kneading the slurry into the polyester. The component B, e.g. aluminum oxide, is produced by subjecting aluminum successively to alkylation, hydrolysis and thermal decomposition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester composition excellent in flatness, abrasion resistance and scratch resistance when formed into a molded product because it contains inorganic particles having a specific shape, and a film comprising the same. is there.

[0002]

2. Description of the Related Art Polyester represented by polyethylene terephthalate has excellent physical and chemical properties and is widely used as a molded article such as a film or a fiber. Usually, when the polyester is used after being processed into a molded product, its physical and chemical properties, such as slipperiness and abrasion resistance, have a great influence on the workability in the manufacturing process and the processing process in various applications. Will be affected. For example, when they are used as a base film for magnetic tape, if their properties are insufficient, they are coated during the manufacturing process of the magnetic tape.
The friction between the tiling roll and the film increases,
The film is wrinkled or scratched. Also, abrasion powder of the film is liable to be generated, resulting in coating omission in the step of applying the magnetic layer, resulting in omission of magnetic recording (drop-out).

Conventionally, a number of methods have been proposed in which fine particles are contained in polyester for the purpose of improving the slipperiness of the film to give unevenness to the surface of a molded product, and some of them have been put into practical use. For example, inert inorganic particles such as kaolin, talc, calcium carbonate, silicon dioxide, and titanium dioxide, or organic polymers such as benzoguanamine / formaldehyde resin, polytetrafluoroethylene-hexafluoropropylene copolymer, and polyphenyl ester resin. There is a method of adding particles to a polyester synthesis reaction system (for example, JP-A-55-133431 and JP-A-57-125247).

However, the method of adding the inert inorganic particles generally lacks the affinity with polyester, and when a film is formed, for example, a void is generated due to the particle shape. Further, coarse particles are often mixed in, and even if pulverization and classification operations are performed to remove them, it is still inevitable to mix coarse particles. When voids are generated or coarse particles are present in this manner, transparency is significantly reduced in a film required for transparency such as plate-making printing and microfilm, and electrical characteristics are reduced in a capacitor-use film. Adversely affect. Furthermore, the magnetic tape
In the film for the magnetic tape, the electromagnetic conversion characteristics are deteriorated,
Particles fall off the surface of the molded product, causing drop-out and impairing film quality.

On the other hand, the method of adding organic polymer particles is
Generally, it has a good affinity with polyester, but it is difficult to obtain uniform particles, and even if it is obtained, the dispersibility in the polyester is poor, such as aggregation in the polyester, and the inclusion of coarse particles cannot be avoided.

[0006]

The object of the present invention is to eliminate the above-mentioned problems of the prior art, and in particular, the inclusion of needle-like inorganic particles having a specific form in the film makes it possible to improve the flatness and durability. It is intended to provide a polyester composition having excellent abrasion resistance and scratch resistance, and a film comprising the same.

[0007]

The above-mentioned object of the present invention is achieved by the following constitution. (1) A polyester composition characterized by containing acicular inorganic particles in a polyester comprising a difunctional acid component mainly containing an aromatic dicarboxylic acid and a glycol component, (2)
The acicular inorganic particles are at least one selected from the group consisting of titanium oxide, aluminum oxide and zirconium oxide, (3) the polyester composition as described in (1) or (2) above. A biaxially oriented polyester film comprising the polyester composition described in 1.
(4) A biaxially oriented polyester film as described in (3) above, which is a laminated film in which the polyester composition is arranged on at least one side, and (5) needle-like inorganic particles contained in the polyester film. To form an aggregate satisfying the following formula (I): The biaxially oriented polyester film as described in (3) or (4) above. 0.05 ≦ B / A ≦ 0.6 (I) (In the formula, A is the length A parallel to the film length direction of the aggregate.
μm, B represents the length Bμm parallel to the thickness direction of the aggregate)

The needle-like inorganic particles in the present invention include needle-like primary particles having similar shapes such as rod-like, fibrous and columnar particles. The acicular inorganic particles used in the present invention have a major axis of 1 μm or less, preferably 0.5 μm or less, and a major axis / minor axis axial ratio of 3 or more, preferably 5 or more. (Here, the long axis is a plan view of a particle observed with a transmission electron microscope, the length between two parallel lines with the longest distance in contact with the contour, the short axis is a plan view of the particle, and is in contact with the contour. It represents the length between parallel lines that are perpendicular to the parallel lines that determine the major axis.) Further, such particles may have dents and projections as long as the effects of the present invention are not impaired.

Examples of such acicular inorganic particles include kaolin, zinc oxide, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, iron oxide, calcium carbonate, calcium sulfate, silicon carbide, silicon nitride, carbon, Examples include asbestos. Titanium oxide, aluminum oxide and zirconium oxide are preferable in terms of abrasion resistance. The needle-shaped inorganic particles of the present invention are not limited to one kind as long as they are needle-shaped inorganic particles, and it is possible to use a mixture of several kinds. Further, the surface of these particles may be treated with another compound, or may contain a small amount of impurities.

The method for producing these acicular inorganic particles is not particularly limited. For example, in the case of aluminum oxide, it can be obtained by the steps of alkylation, hydrolysis and thermal decomposition using aluminum as a starting material (organic aluminum hydrolysis method). ),
The particle size is arbitrarily controlled by the firing temperature.

When blending the needle-shaped inorganic particles in the present invention with polyester, it is preferable to use a glycol used as a raw material of polyester and a copolymerization component, for example, a slurry dispersed in the following medium. The medium of the slurry is water, methanol, ethylene glycol, 1,4
Examples include butanediol, neopentyl glycol, propylene glycol, and diethylene glycol. Further, upon compounding, it may be added directly to the polymerization reaction system or may be kneaded into the polyester. The former may be added to the polymerization reaction system at any time, but is preferably from before the transesterification reaction to before the pressure reduction of the polycondensation reaction.

In the latter case of kneading, either a method of drying the particles and kneading them into the polyester or a method of directly kneading them under reduced pressure in a slurry state may be used. Considering the dispersibility, it is preferable to directly knead in a high shearing kneading machine in a slurry state while reducing the pressure. Further, the content of needle-shaped inorganic particles in the polyester in the present invention is 0.001 to
It is preferably 10% by weight, more preferably 0.01 to 5.0% by weight.

The acicular inorganic particles in the present invention preferably form an agglomerate in the film, and the agglomerate form is such that, in the film, the length A μm in the direction parallel to the film length direction and the film thickness. Length parallel to direction Bμ
The ratio m / B / A is 0.05 or more and 0.6 or less, and more preferably 0.1 to 0.5.

When the value of B / A is less than 0.05, the cohesive force of the particles themselves decreases, and the scratch resistance and abrasion resistance become insufficient. On the other hand, when the value of B / A exceeds 0.6, the uniformity of the height of protrusions is deteriorated and the abrasion resistance is lowered, which is not preferable.

The fact that B / A is less than 1 means that the film is oriented in the film surface direction by film stretching, and when the value of B / A is 0.05 or more and 0.6 or less, the film is Stretching is performed uniformly, and the aggregated particles oriented in the plane direction have a strong structure against external force. That is, as compared with the agglomerates in which B / A does not fall within the range of 0.05 to 0.6, more excellent scratch resistance,
Exhibits wear resistance. Further, by orienting the agglomerates at the time of stretching the film, it is possible to form protrusions having a uniform height on the film surface, and it is possible to obtain a film having both scratch resistance, abrasion resistance and surface flatness.

In such aggregates, the length A is preferably 0.01 to 3.0 μm, more preferably 0.05 to 1.0 μm in terms of scratch resistance and running property. . From the viewpoint of scratch resistance and flatness, the length of B is preferably 0.005 to 1.5 μm, and more preferably 0.01 to 0.2 μm.

The particles A and B can be controlled by controlling the dispersed state of the acicular inorganic particles, the stretching speed during film formation, the temperature, and the stretching ratio.

The polyester used in the present invention is a polyester containing an aromatic dicarboxylic acid as a main difunctional acid component and a glycol as a main component. The polyester is a substantially linear polymer and has a fiber and film forming property by melt molding.

Examples of the aromatic dicarboxylic acid used in the present invention include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenylethanedicarboxylic acid and the like. As the glycol component, aliphatic glycol such as alkylene glycol such as ethylene glycol, tetramethylene glycol, hexamethylene glycol or alicyclic diol such as cyclohexane dimethanol. And so on.

More specifically, the polyester used in the present invention preferably contains, for example, alkylene terephthalate or alkylene naphthalate as a main constituent. Further, 20 mol% or less of each of the dicarboxylic acid component and the glycol component is used for the other dicarboxylic acid component and the glycol component.
It may be replaced with a red component. As such a copolymerization component, in addition to the components described above, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, hydroquinone, polyethylene glycol, polypropylene glycol and the like can be mentioned. Further, as a copolymerization component, an aromatic oxycarboxylic acid such as hydroxybenzoic acid, an aliphatic oxycarboxylic acid such as ω-hydroxyaproic acid, or the like can be used.

The polyester used in the present invention can be synthesized by a known method. For example, in the case of polyethylene terephthalate, the polyester can be obtained by reacting terephthalic acid or dimethyl terephthalate with ethylene glycol to form a low polymer and then polycondensing. At this time, a known metal compound as a transesterification reaction catalyst, for example, calcium, magnesium, lithium, manganese, zinc, cobalt and other acetates, oxalates, halides, hydroxides, and an antimony compound as a polymerization catalyst, A titanium compound or a germanium compound may be used. Further, a known phosphorus compound such as phosphoric acid, phosphorous acid, phosphonic acid and their lower alkyl esters and phenyl esters may be added as a color preventing agent during the reaction.

The polyester composition of the present invention comprises a composition comprising the above polyester and acicular inorganic particles as a main component, but various polymers may be blended within a range not impairing the object of the present invention. Organic additives such as antioxidants, heat stabilizers, lubricants, and ultraviolet absorbers may be added to the extent that they are usually added.

Particles other than the acicular inorganic particles of the present invention may be used in combination in order to obtain the running property of the film. Examples of such particles include inorganic particles such as calcium carbonate, titanium oxide, silicon oxide, and calcium phosphate, and silicone.
Polymerization reaction of cross-linked polymer particles such as styrene, styrene-divinylbenzene copolymer, ethylvinylbenzene-divinylbenzene copolymer, or at least one of alkali metal and alkaline earth metal and phosphorus as a component. Examples include so-called internal particles precipitated in the system.

The particle size of these particles is preferably larger than that of the acicular inorganic particles of the present invention, preferably 0.1 to 2 μm. The content in the polyester is 0.00
5-10% by weight is preferred.

When the polyester thus produced is used to form a film, for example, it can be produced according to the conventionally accumulated method for producing a biaxially stretched film. For example, polyester containing acicular inorganic particles is melt-cast into an amorphous unstretched film, and then the unstretched film is biaxially stretched, heat-fixed, and if necessary, subjected to relaxation heat treatment. Manufactured by. At that time, the film surface characteristics are not only determined by the size-dispersed state of the acicular inorganic particles in the slurry, but are also changed by the stretching conditions, and therefore are appropriately selected from the conventional stretching conditions. Further, since the void, density, heat shrinkage ratio, etc. of the film also change depending on the temperature during drawing, heat treatment, the draw ratio, the drawing speed, etc., it is preferable to determine the conditions that simultaneously satisfy these characteristics. For example, the stretching temperature is such that the first stage stretching temperature (for example, the longitudinal stretching temperature: T ₁ ) is (Tg-10) to (Tg + 4).
5) From the range of ℃ (however, Tg: glass transition temperature of polyester), the second stage stretching temperature (for example, the transverse stretching temperature:
T ₂ ) may be selected from the range of (T ₁ −15) to (T ₁ +40) ° C. Further, the stretching ratio is preferably selected from the range in which the stretching ratio in the uniaxial direction is 2.5 times or more, particularly 3 times or more and the area magnification is 8 times or more, particularly 10 times or more. Furthermore, the heat setting temperature is preferably selected from the range of 180 to 250 ° C., and more preferably 200 to 230 ° C. This makes it possible to obtain a biaxially oriented polyester film having excellent slipperiness and abrasion resistance. This biaxially oriented polyester film is preferably used for a base film of a magnetic recording medium, especially for a base film of a magnetic tape, but is not limited to this, and it can be used for electrical applications, packaging applications and vapor deposition films. It can be widely applied to other fields. Moreover, not only such a film but also a yarn having excellent surface characteristics can be obtained by molding into a fiber.

The film of the present invention can be used as a single-layer film, of course, but when it is used in the form of a biaxially oriented film after being laminated on at least one side, the uniformity of the film surface, slipperiness and abrasion resistance are further improved. It is preferable because it becomes good. Also when used as a laminated film, it is particularly preferable that the acicular inorganic particle aggregates satisfy the above formula (I). In this case, an ordinary polyethylene terephthalate film or the like is preferably used as the base film.

The film thickness of the laminated portion (layer containing acicular inorganic particles) in the above is 0.01 to 10 with respect to the aggregate diameter (B μm) of acicular inorganic particles to be added in the film.
If the amount is doubled, especially 0.1 to 5, the slipperiness and abrasion resistance are particularly good, which is preferable.

[0028]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples. (1) Primary particle size of particles A slurry of particles is diluted with a mixed solvent of methanol and water, the particles are dispersed and fixed on a collodion film, and the particles are observed using a transmission electron microscope. 1000 particles were measured and the average was calculated.

(2) Intrinsic viscosity of polymer Measured at 25 ° C. using o-chlorophenol as a solvent.

(3) Morphology of acicular inorganic particles in the film An ultrathin section of 0.2 μm thickness having a surface formed by the film length direction and the film thickness direction was cut out from the film and observed with a transmission electron microscope. Then, the length Aμm of the acicular inorganic particle aggregate in the film length direction and the length Bμm in the film thickness direction of 1000 aggregates were measured, and the average thereof was obtained.

(4) Film average surface roughness (Ra) According to the method specified in JIS B-0601,
Using a Fucom surface roughness meter, needle diameter 2 μm, load 70 m
g, cutoff 0.08 mm, measurement reference length 0.25 mm
The center line average roughness (Ra) was measured under the conditions of.

(5) Evaluation of abrasion resistance The polyester composition obtained in the example was made into a biaxially stretched film by the method shown in the example, the film was slit into 1/2 inch, and a tape running tester was used. TBT-300
(Manufactured by Yokohama System Laboratory Co., Ltd.) at 25 ° C, 6
After repeatedly running 1000 times in an atmosphere of 0% RH,
The white shavings (white powder) adhering to the guide part are visually determined.

Here, the guide diameter is 8 mmφ, the guide material is SUS-27 (surface roughness 0.2S), the winding angle is 180 °, and the tape running speed is 3.3 cm / sec. The evaluation criteria are as follows. Grades 1 and 2 were accepted. 1st class ……………… White powder generation is extremely low 2nd class ……………… White powder generation is low 3rd class ……………… White powder generation is slightly high 4th class ……………… White powder generation rate is Very many

(6) Evaluation of Scratch Resistance The polyester composition obtained in the example was made into a biaxially stretched film by the method shown in the example, and a tape obtained by slitting the film into 1/2 inch was used as a metal pin ( Diameter 6 mm, surface roughness Ra 0.045 μm, Rt 2.5 μm), load 20
2 at 0g, wrapping angle 90 °, running speed 3.3cm / sec
Scrape to 0 cm. Aluminum is vacuum-deposited on the tape scraping surface, and the number of scratches is checked by a differential interference microscope (magnification: 100).
10 times in the tape width direction, and the number of scratches per tape width was determined. Grades 1 and 2 were accepted. 1st grade ……………… No scratches 2nd grade ……………… 1 to 3 scratches 3rd grade ……………… 4 to 10 scratches 4th grade ……………… 11 or more scratches

Example 1 (1) Synthesis of polyethylene terephthalate composition (X) 10 parts by weight of acicular titanium oxide particles having a major axis of 0.1 μm and an axial ratio of 5 and 90 parts by weight of ethylene glycol were mixed. Then, the mixture was rapidly stirred at room temperature for 3 hours to obtain acicular titanium oxide particles / ethylene glycol slurry (a).

On the other hand, 0.06 parts by weight of magnesium acetate as a catalyst was added to 100 parts by weight of dimethyl terephthalate and 64 parts by weight of ethylene glycol to carry out a transesterification reaction, and then the reaction product was adjusted beforehand. Slurry (a)
5 parts by weight, 0.03 parts by weight of the catalyst antimony trioxide,
Polycondensation reaction was carried out by adding 0.03 part by weight of trimethyl phosphate to obtain a polyethylene terephthalate composition (X) having an intrinsic viscosity of 0.615.

(2) Production of polyester film The polymer obtained was dried under reduced pressure at 180 ° C. for 3 hours (3 Tor).
r). This polymer is then fed to the extruder, 290
The film was melted at 0 ° C., wound around a casting drum having a surface temperature of 30 ° C., cooled and solidified to obtain an unstretched film. After that, the film was stretched at 90 ° C in the length and width three times, and then 22 times.
Heat treatment was performed at 0 ° C. for 15 seconds to obtain a biaxially oriented polyester film.

When the aggregate of needle-shaped titanium oxide particles in this film was observed with a transmission electron microscope, A was 0.5 μm.
m and B were 0.15 μm, and B / A was 0.3. Further, when the film was evaluated, it was Ra 0.009, and the film was very excellent in abrasion resistance and scratch resistance.

Examples 2 to 5 Biaxially oriented polyester films were obtained in the same manner as in Example 1 except that the type of needle-shaped inorganic particles and the sizes A and B of the needle-shaped inorganic particle aggregates in the film were different. It was The evaluation results of these films are shown in Tables 1 and 2, and the films were very excellent in flatness, abrasion resistance and scratch resistance.

Examples 6 and 7 (3) Synthesis of polyethylene terephthalate (Y) 100 parts by weight of dimethyl terephthalate, 64 parts by weight of ethylene glycol and 0.06 magnesium acetate as a catalyst.
The transesterification reaction was carried out by adding parts by weight. Next, 0.03 parts by weight of antimony trioxide and trimethyl phosphate were added.
Polyethylene terephthalate (Y) having an intrinsic viscosity of 0.620 was obtained by adding 0.03 part by weight of poly (ethylene glycol) to the polycondensation reaction.

(4) Production of laminated polyester film Polyethylene terephthalate composition obtained in the same manner as in Example 1 except that the acicular inorganic particles added to the polyethylene terephthalate (Y) were changed. (X ') at 290 ° C
Was melt-extruded into a laminated unstretched film. After that, the film was stretched at 90 ° C in the length and width three times, and then 22 times.
Heat treatment at 0 ° C. for 15 seconds, a polyethylene terephthalate (Y) layer having a thickness of 8.0 μm, and a polyethylene terephthalate composition layer having a thickness of 0.2 μm laminated thereon. An oriented polyester film was obtained. However, the addition amount of the needle-shaped inorganic particles in Table 2 shows the content in the polyester composition (X ′) containing the needle-shaped inorganic particles. When this film was evaluated, as shown in Table 2, it was a film excellent in flatness, abrasion resistance and scratch resistance.

Examples 8 and 9 A polyethylene terephthalate composition was obtained in the same manner as in Example 1 except that the kind of particles used in combination was changed. After the polyethylene terephthalate composition (X) of Example 1 and the above polyethylene terephthalate composition were chip-blended at a ratio of 1: 1, a biaxially oriented polyester film was obtained in the same manner as in Example 1. It was The evaluation results of the film are shown in Table 3, and the film was very excellent in flatness, abrasion resistance and scratch resistance.

[0043]

[Table 1]

[Table 2]

[Table 3] Comparative Examples 1 to 4 A biaxially oriented polyester film was obtained in the same manner as in Example 1, except that the type of particles and the sizes A and B of the particle aggregates in the film were changed. The evaluation results of these films are shown in Table 4, but they were not within the scope of the present invention, so that the films were not satisfactory in both abrasion resistance and scratch resistance.

[0044]

[Table 4]

[0045]

Since the polyester composition of the present invention contains the acicular inorganic particles having a specific shape, it forms a specific aggregate in the film, which results in flatness, abrasion resistance, and abrasion resistance. It has excellent scratch resistance and is suitable for magnetic tape applications, photography, plate making applications, capacitor applications and the like.

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Claims (5)

[Claims] 1. A polyester composition comprising acicular inorganic particles in a polyester comprising a difunctional acid component mainly containing an aromatic dicarboxylic acid and a glycol component. 2. The polyester composition according to claim 1, wherein the acicular inorganic particles are at least one selected from the group consisting of titanium oxide, aluminum oxide and zirconium oxide. 3. A biaxially oriented polyester film comprising the polyester composition according to claim 1 or 2. 4. The biaxially oriented polyester film according to claim 3, which is a laminated film in which the polyester composition is arranged on at least one side. 5. The biaxially oriented polyester film according to claim 3, wherein the acicular inorganic particles contained in the polyester film form an aggregate satisfying the following formula (I). 0.05 ≦ B / A ≦ 0.6 (I) (In the formula, A is the length A parallel to the film length direction of the aggregate.
μm, B is the length Bμ of the aggregate parallel to the film thickness direction
represents m)