JP3309497B2 - Polyester composition and film comprising the same - 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 having excellent flatness, abrasion resistance and scratch resistance when formed into a molded article containing inorganic particles of a specific shape, and a film comprising the same. is there.

[0002]

2. Description of the Related Art Polyesters represented by polyethylene terephthalate have excellent physical and chemical properties and are widely used as molded products such as films and fibers. Usually, when the polyester is processed into a molded product and used, its physical and chemical properties, such as slipperiness and abrasion resistance, greatly affect workability in a manufacturing process and a processing process in various applications. Will be exerted. For example, when these properties are insufficient when used as a base film of a magnetic tape, the core tape may be damaged during the manufacturing process of the magnetic tape.
The friction between the Ting Roll and the film increases,
The film is wrinkled or scratched. In addition, abrasion powder of the film is likely to be generated, and a coating omission occurs in the step of applying the magnetic layer, thereby causing a drop out of magnetic recording.

[0003] Hitherto, many methods have been proposed in which fine particles are contained in polyester to impart irregularities to the surface of a molded product in order to improve the slipperiness of the film, and some of them have been put to 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 polyphenylester resin There is a method of adding particles to a polyester synthesis reaction system (for example, JP-A-55-133431, JP-A-57-125247, etc.).

[0004] However, the method of adding inert inorganic particles generally lacks affinity for polyester. For example, when a film is formed, voids are generated due to the particle shape. Further, coarse particles are often mixed in, and even if pulverization and classification operations are performed to remove these, mixing of the coarse particles cannot be avoided. When voids are formed or coarse particles are present, the transparency is significantly reduced in a film requiring transparency, such as for plate making, for a microfilm, and the like, and the electrical characteristics are deteriorated in a film for a capacitor. Adversely affect. Furthermore, magnetic tape
In the case of film for media, the electromagnetic conversion characteristics are reduced,
Particles fall off the surface of the molded article, causing drop-out, which impairs film quality.

On the other hand, a method for adding organic polymer particles is as follows.
In general, it has good affinity for polyester, but it is difficult to obtain uniform particles, and even if obtained, poor dispersibility in polyester such as agglomeration in polyester is inevitable, and mixing of coarse particles cannot be avoided.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art. In particular, the film contains needle-like inorganic particles having a specific form, thereby achieving flatness and resistance to film. An object of the present invention is to provide a polyester composition excellent in abrasion resistance and scratch resistance, and a film comprising the same.

[0007]

The object of the present invention is attained by the following constitution. (1) A polyester comprising a difunctional acid component mainly composed of an aromatic dicarboxylic acid and a glycol component having a major axis of 1 μm or less.
Polyester composition characterized by containing needle-like inorganic particles below (2) needle-like inorganic particles are titanium oxide, aluminum oxide,
A polyester composition according to the above (1), which is at least one member selected from the group consisting of zirconium oxide; and (3) a biaxial composition comprising the polyester composition according to the above (1) or (2). (4) a biaxially oriented polyester film according to the above (3), which is a laminated film in which the polyester composition is disposed on at least one surface; (5) a polyester film contained in the polyester film The biaxially oriented polyester film according to the above (3) or (4), wherein the acicular inorganic particles form an aggregate satisfying the following formula (I). 0.05 ≦ B / A ≦ 0.6 (I) (where A is the length A of the aggregate in parallel with the film length direction)
μm, B is the length Bμ parallel to the film thickness direction of the aggregate.
m)

[0008] The needle-like inorganic particles in the present invention are those in which the primary particles are needle-like, and include rod-like, fiber-like, and columnar-like similar particles. The needle-like 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 ratio of 3 or more, preferably 5 or more. (Here, the long axis is the length between the two parallel lines at the longest interval in contact with the contour, with respect to the plan view of the particle observed with the transmission electron microscope, and the short axis is the contact with the contour, It represents the length between parallel lines perpendicular to the parallel line that determines the major axis.) 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, Asbestos and the like. Preferably, titanium oxide, aluminum oxide, and zirconium oxide are desirable from the viewpoint of abrasion resistance. The needle-like inorganic particles of the present invention are not limited to one kind as long as they are needle-like inorganic particles, and a mixture of several kinds can be used. In addition, these particles may be surface-treated with another compound, or may contain a small amount of impurities.

The method for producing these needle-shaped inorganic particles is not particularly limited. For example, in the case of aluminum oxide, it can be obtained by using aluminum as a starting material and subjecting it to alkylation, hydrolysis and thermal decomposition processes (organoaluminum hydrolysis method). ),
The particle diameter is arbitrarily controlled by the firing temperature.

In blending the needle-like inorganic particles in the present invention with the polyester, it is preferable to use a glycol used as a raw material and a copolymer component of the polyester, for example, a slurry dispersed in the following medium. Water, methanol, ethylene glycol, 1,4
-Butanediol, neopentyl glycol, propylene glycol, diethylene glycol and the like. In addition, it may be directly added to the polymerization reaction system or may be kneaded into polyester. The timing of addition to the former polymerization reaction system is optional, but is preferably from before the transesterification reaction to before the start of the pressure reduction in the polycondensation reaction.

In the latter kneading method, a method of drying and kneading the particles into polyester or a method of directly kneading while reducing the pressure in a slurry state may be used. Considering the dispersibility, it is preferable to directly knead the slurry in a slurry state while reducing the pressure in a kneading machine having a high shear force. Further, the content of the acicular inorganic particles in the polyester in the present invention is 0.001 to
It is preferably 10% by weight, and more preferably 0.01 to 5.0% by weight.

It is preferable that the acicular inorganic particles in the present invention form an aggregate in the film, and the form of the aggregate in the film is a length A μm in a direction parallel to the film length direction and a thickness of the film. Length Bμ parallel to the direction
The ratio m / B / A is in the range of 0.05 or more and 0.6 or less, more preferably in the range of 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 the abrasion resistance become insufficient. On the other hand, when the value of B / A exceeds 0.6, the uniformity of the height of the projections deteriorates, and the abrasion resistance decreases, which is not preferable.

The fact that B / A is smaller than 1 means that the film is oriented in the film surface direction by stretching the film, and that the B / A value becomes 0.05 or more and 0.6 or less when the film is stretched. The agglomerated particles which are stretched uniformly and oriented in the plane direction have a strong structure against external force. That is, as compared to aggregates in which B / A does not fall within the range of 0.05 to 0.6, more excellent scratch resistance,
Develops abrasion resistance. Further, since the aggregates are oriented at the time of film stretching, projections having a uniform height can be formed on the film surface, and a film having scratch resistance, abrasion resistance and surface flatness can be obtained.

The length of A of such an aggregate is preferably 0.01 to 3.0 μm, more preferably 0.05 to 1.0 μm, in view of scratch resistance and running properties. . The length of B is preferably from 0.005 to 1.5 μm from the viewpoint of scratch resistance and flatness, and more preferably from 0.01 to 0.2 μm.

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

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

The aromatic dicarboxylic acid used in the present invention includes, for example, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenylethanedicarboxylic acid and the like. Examples of the glycol component include aliphatic glycols, for example, alkylene glycols such as ethylene glycol, tetramethylene glycol, and hexamethylene glycol, and alicyclic diols such as cyclohexanedimethanol. And the like.

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

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, followed by polycondensation. At this time, a metal compound known as a transesterification catalyst, for example, acetates, oxalates, halides, hydroxides such as calcium, magnesium, lithium, manganese, zinc, and cobalt, and an antimony compound as a polymerization catalyst, A titanium compound, a germanium compound, or the like may be used. In addition, a known phosphorus compound such as phosphoric acid, phosphorous acid, phosphonic acid and their lower alkyl esters and phenyl esters may be added during the reaction as a coloring inhibitor.

The polyester composition of the present invention comprises, as a main component, a composition comprising the above-mentioned polyester and needle-like inorganic particles, but it may be blended with various polymers as long as the object of the present invention is not impaired. Organic additives such as antioxidants, heat stabilizers, lubricants and ultraviolet absorbers may be added to the extent that they are usually added.

Further, in order to obtain the running property of the film, particles other than the acicular inorganic particles of the present invention may be used in combination. Examples of such particles include inorganic particles such as calcium carbonate, titanium oxide, silicon oxide, and calcium phosphate;
Polymer particles such as styrene, styrene-divinylbenzene copolymer, ethylvinylbenzene-divinylbenzene copolymer, or polyester polymerization reaction in which at least one of alkali metal and alkaline earth metal and phosphorus are part of the constituent components 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, and more 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 molded into, for example, a film, it can be produced in accordance with a conventionally accumulated method for producing a biaxially stretched film. For example, melt-forming a polyester containing needle-like inorganic particles into an amorphous unstretched film, and then stretching the unstretched film biaxially, heat setting, and, if necessary, performing a relaxation heat treatment. Manufactured by At this time, the film surface characteristics are not only determined by the size dispersion state of the acicular inorganic particles in the slurry, but also vary according to the stretching conditions. Also, since the film void, density, heat shrinkage, and the like also change depending on the temperature during stretching and heat treatment, the stretching ratio, the stretching speed, and the like, it is preferable to determine conditions that simultaneously satisfy these characteristics. For example, the stretching temperature in the first stage stretching temperature (for example, the longitudinal stretching temperature: T ₁ ) is (Tg−10) to (Tg + 4).
5) From the range of ° C. (where 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. The stretching ratio is preferably selected from a range where 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. Further, the heat setting temperature is preferably selected from the range of 180 to 250 ° C, more preferably 200 to 230 ° C. As a result, a biaxially oriented polyester film having excellent slipperiness and abrasion resistance can be obtained. This biaxially oriented polyester film is preferably used for a base film of a magnetic recording medium, especially for a magnetic tape, but is not limited thereto, and may be used for electric applications, packaging applications and films for vapor deposition. It can be widely applied to other fields. Further, not only such a film but also a fiber having excellent surface characteristics can be obtained by molding into a fiber.

The film of the present invention can of course be used in the form of a single-layer film. However, when the film is laminated on at least one side and then used in the form of a biaxially oriented film, the uniformity, smoothness and abrasion resistance of the film surface are further improved. It is preferable because it becomes good. Also when used as a laminated film, it is particularly preferred that the acicular inorganic particle aggregates satisfy the above-mentioned 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 (the layer containing the acicular inorganic particles) in the above is 0.01 to 10 with respect to the aggregation diameter (B μm) of the acicular inorganic particles to be added in the film.
When it is multiplied, especially 0.1 to 5 times, the slipperiness and the abrasion resistance are particularly good, which is preferable.

[0028]

Next, the present invention will be specifically described with reference to Examples and Comparative Examples. (1) Primary particle diameter of particles The particle slurry 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 determined.

(2) Intrinsic Viscosity of Polymer The polymer was measured at 25 ° C. using o-chlorophenol as a solvent.

(3) Morphology of the Acicular Inorganic Particles in the Film From the film, an ultra-thin section having a thickness of 0.2 μm having a surface formed by the film length direction and the film thickness direction is cut out and observed with a transmission electron microscope. Then, the length A μm of the needle-like inorganic particle aggregate in the film length direction and the length B μm of the film thickness direction in the film thickness direction were measured for 1000 aggregates, and the average was obtained.

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

(5) Evaluation of abrasion resistance The polyester composition obtained in the example was made into a biaxially stretched film according to the method shown in the example, and the film was slit into 1/2 inch. TBT-300
(Yokohama System Laboratory Co., Ltd.) at 25 ° C, 6
After running 1000 times repeatedly in the atmosphere of 0% RH,
The white shaved powder (white powder) attached to the guide portion is visually determined.

Here, the guide diameter is 8 mmφ, the guide material is SUS-27 (surface roughness 0.2 S), the winding angle is 180 °, and the tape running speed is 3.3 cm / sec. The evaluation criteria are as follows. Classes 1 and 2 were accepted. First-class: Very low white powder generation Second-class: Low white powder generation Third-grade: slightly higher white powder generation Grade 4: High-level white powder generation Very much

(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 the tape obtained by slitting the film to 1/2 inch was inserted into a metal pin ( 6 mm diameter, surface roughness Ra 0.045 μm, Rt 2.5 μm)
0g, wrap angle 90 °, running speed 3.3cm / sec 2
Rub 0 cm. Aluminum was vacuum-deposited on the tape rubbed surface, and the number of scratches was measured using a differential interference microscope (100 magnification).
), And the number of scratches per tape width was determined arbitrarily at 10 places in the tape width direction. Classes 1 and 2 were accepted. Grade 1 ... No scratches Grade 2 ... 1-3 scratches Grade 3 ... 4-10 scratches Grade 4 ... 11 scratches or more

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 were mixed with 90 parts by weight of ethylene glycol. 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, a transesterification reaction was performed by adding 0.06 parts by weight of magnesium acetate as a catalyst to 100 parts by weight of dimethyl terephthalate and 64 parts by weight of ethylene glycol, and then the reaction product was adjusted first. Slurry (a)
5 parts by weight, 0.03 part by weight of antimony trioxide as a catalyst,
0.03 parts by weight of trimethyl phosphate was added to carry out a polycondensation reaction to obtain a polyethylene terephthalate composition (X) having an intrinsic viscosity of 0.615.

(2) Production of polyester film The obtained polymer was dried under reduced pressure at 180 ° C. for 3 hours (3 Torr).
r). Thereafter, the polymer was supplied to an extruder, and 290
C. and melted around a casting drum having a surface temperature of 30.degree. C. to be cooled and solidified to obtain an unstretched film. Thereafter, the film is stretched three times vertically and horizontally at 90 ° C.
Heat treatment was performed at 0 ° C. for 15 seconds to obtain a biaxially oriented polyester film.

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

Examples 2 to 5 A biaxially oriented polyester film was obtained in the same manner as in Example 1, except that the type of the acicular inorganic particles and the sizes A and B of the acicular inorganic particle aggregates in the film were different. 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 and 64 parts by weight of ethylene glycol were mixed with 0.06% of magnesium acetate as a catalyst.
The transesterification reaction was performed by adding parts by weight. Next, 0.03 parts by weight of antimony trioxide and trimethyl phosphate
Then, 0.03 parts by weight of the polymer was added and a polycondensation reaction was carried out to obtain polyethylene terephthalate (Y) having an intrinsic viscosity of 0.620.

(4) Production of Laminated Polyester Film A polyethylene terephthalate composition obtained in the same manner as in Example 1 except that the acicular inorganic particles added on the polyethylene terephthalate (Y) were changed. (X ′) at 290 ° C.
To form a laminated unstretched film. Thereafter, the film is stretched three times vertically and horizontally at 90 ° C.
Heat treated at 0 ° C. for 15 seconds, and a biaxial as shown in Table 2 wherein 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 acicular inorganic particles in Table 2 indicates the content in the polyester composition (X ′) containing the acicular inorganic particles. When this film was evaluated, as shown in Table 2, the film was very 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 type of particles used in combination was changed. After chip-blending the polyethylene terephthalate composition (X) of Example 1 and the polyethylene terephthalate composition at a ratio of 1: 1, a biaxially oriented polyester film was obtained in the same manner as in Example 1. 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 Biaxially oriented polyester films were obtained in the same manner as in Example 1 except that the types 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 were not within the scope of the present invention, and thus the films were not satisfactory in both abrasion resistance and scratch resistance.

[0044]

[Table 4]

[0045]

The polyester composition of the present invention forms specific agglomerates in the film because it contains needle-like inorganic particles having a specific shape, thereby providing flatness, abrasion resistance, and resistance to abrasion. It has excellent scratch resistance and is suitable for magnetic tape applications, photography, plate making applications, capacitor applications, and the like.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 67/00-67/03

Claims (5)

(57) [Claims] A polyester comprising a difunctional acid component mainly composed of an aromatic dicarboxylic acid and a glycol component has a long axis.
A polyester composition containing needle-like inorganic particles of 1 μm or less . 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. 4. The biaxially oriented polyester film according to claim 3, wherein the polyester composition is a laminated film having at least one surface thereof. 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) (where A is the length A of the aggregate in parallel with the film length direction)
μm, B is the length Bμ parallel to the film thickness direction of the aggregate.
m)