JPH07242800A - Polyester composition - Google Patents

Abstract

PURPOSE:To obtain a polyester compsn. which gives a film excellent in resistances to abrasion and scratch and suitable for a magnetic recording medi um. CONSTITUTION:This polyester compsn. contains at least either an alkali metal compd. or an alkaline earth metal compd. and a phosphorus compd. in such amts. as to satisfy the relation: 5<=M/P<=500 (wherein M is the total number of moles of the alkali and alkaline earth metal compds. contained in 10<6>g of a polyester resin; and P is the total number of moles of the phosphorus compd. contained in 10<6>g of the resin).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to polyester compositions. More specifically, the present invention relates to a polyester composition suitable for obtaining a film having excellent abrasion resistance and scratch resistance (referring to the property of being hard to be scratched).

[0002]

2. Description of the Related Art Generally, thermoplastic polyesters such as polyethylene terephthalate have excellent mechanical properties and chemical properties and are widely used as molded articles such as films and fibers. However, when the polyester is processed into a molded product, there is a problem that productivity is lowered due to lack of slipperiness. As a method for improving such a problem, conventionally, a method of dispersing particles in polyester to give unevenness to the surface of a molded article has been performed. For example, Japanese Patent Application Laid-Open No. 52-86471 proposes a method of using inorganic particles having a specified specific surface area, and Japanese Patent Application Laid-Open No. 59-171623 proposes a method of using spherical colloidal silica having a diameter of 0.1 to 1 μm. These methods are effective in solving the problem of slipperiness, but when formed into molded products, the wear resistance and scratch resistance cannot be made to a satisfactory level.

When the abrasion resistance of a molded product, for example, a film for magnetic tape is low, abrasion powder of the film is apt to be generated during the manufacturing process of the magnetic tape, resulting in coating omission in the process of applying the magnetic layer, resulting in , Cause magnetic recording dropout. In addition, when using a magnetic tape, in most cases, it travels while contacting with recording / reproducing equipment, etc., so abrasion powder generated at the time of contact adheres to the magnetic material, and during recording / reproducing, dropout (drop / drop) of magnetic recording occurs. Out). When the scratch resistance of the molded product, for example, the film for magnetic tape, is low, foreign matter is generated during the manufacturing process of the magnetic tape, and scratches are easily formed on the film surface, resulting in the dropout (dropout) of the magnetic recording. ), Etc., or easily scratch the film surface when the magnetic tape runs at high speed. That is, the magnetic tape film is required to have abrasion resistance and scratch resistance as well as slipperiness, both during the magnetic tape manufacturing process and when used as a magnetic tape.

In order to solve these problems, a method of adding particles (external particle method) and a method of precipitating particles by catalyst residue (internal particle method) have been studied so far. For example, in the former case, Japanese Unexamined Patent Publication (Kokai) No. 62-187724 (Silicone particles), Japanese Unexamined Patent Publication (Kokai) No. 2-129230 (Delta-type aluminum oxide particles), etc., and further, electrostatic castability and the like are added thereto. (Magnesium compounds, etc.), JP-A-2-79524 (magnesium compounds, manganese compounds, etc.), JP-A-4-359048 (magnesium compounds, phosphorus compounds, particles) and the like. Regarding the latter, JP-A-34-5144 (alkali metal salt), JP-A-40-3291 (terephthalate), and JP-A-48-483.
-61556 (containing lithium element), JP-A-5
No. 1-112860 (containing a lithium element, a calcium element, and a phosphorus element) has been proposed, but the effects of improving wear resistance and scratch resistance are still insufficient.

[0005]

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and a film is prepared by blending a specific amount of an alkali metal compound, an alkaline earth metal compound or a phosphorus compound with polyester. It is to provide a composition capable of obtaining a film excellent in slipperiness, abrasion resistance, and scratch resistance by forming a film.

[0006]

The above-mentioned object of the present invention is to provide an amount of an alkali metal compound, at least one compound selected from alkaline earth metal compounds, and a phosphorus compound satisfying the following general formula (I). This is achieved by including it. 5 ≦ M / P ≦ 500 (I) However, in the formula (I), M: the total number of moles of the alkali metal compound and the alkaline earth metal compound contained per 10 ⁶ g of the polyester. P: Total number of moles of phosphorus compound contained per 10 ⁶ g of polyester.

The polyester in the present invention may be any one as long as it can form a film, for example, polyethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate, Polyethylene-1,2-bis (2-chlorophenoxy) ethane-4,4'-dicarboxylate and the like are preferable, but polyethylene terephthalate or polyethylene-2,6-naphthalenedicarboxylate is particularly preferable.

These polyesters include dicarboxylic acids such as adipic acid, isophthalic acid, sebacic acid, phthalic acid, 4,4'-diphenyldicarboxylic acid and their ester-forming derivatives, polyethylene glycol, diethylene glycol, and hexa as copolymerization components. Dioxy compounds such as methylene glycol, neopentyl glycol and polypropylene glycol, oxycarboxylic acids such as p- (β-oxyethoxy) benzoic acid and ester-forming derivatives thereof may be copolymerized.

The alkali metal compound in the present invention is
Although not particularly limited, it is preferably acetate,
Lithium acetate and potassium acetate are particularly preferable. It may also be used as a transesterification catalyst. As the amount of such an alkali metal compound added, if it is too small, as a transesterification catalyst, or in scratch resistance etc., a sufficient effect cannot be obtained, and if it is too large,
The transparency and heat resistance will decrease, so 1 × 10 ^-8
It is particularly preferable that it is ˜1 × 10 ⁻³ mol / g. As the timing of adding such an alkali metal compound, from immediately after the start of the transesterification reaction to immediately before the start of the polymerization reaction, or
It is preferable to add it at any time from after the esterification reaction is substantially completed to immediately before the start of the polymerization reaction. As an addition method, it is preferable to add it as an ethylene glycol solution or an ethylene glycol slurry. These alkali metal compounds may be added in two or more divided portions, or two or more alkali metal compounds may be used in combination.

The alkaline earth metal compound used in the present invention is not particularly limited, but acetates and oxides such as calcium and magnesium are preferable, and magnesium compounds are particularly preferable. The magnesium compound is not particularly limited, but magnesium formate, magnesium acetate, magnesium propionate, magnesium benzoate, magnesium oxalate, magnesium tartrate, magnesium oxide, magnesium hydroxide,
And so on. Of these, magnesium acetate and magnesium oxide are preferable. If the addition amount of these magnesium compounds is too small, a sufficient effect may not be obtained in scratch resistance, and if the addition amount is too large, transparency, heat resistance, etc. may decrease, so 1 × 10 ⁻⁷ to 1
It is preferably ^{x10 -2} mol / g, more preferably 1 x 10 ^-6 to 1 x 10 ^-3 mol / g, and particularly preferably 5 x 10 ^{-5 to} 5 x 10 ^-3 mol / g. The magnesium compound is preferably added at any time from immediately after the start of the transesterification reaction to immediately before the start of the polycondensation reaction, and the addition method is an ethylene glycol solution or an ethylene glycol slurry. Preferably. These magnesium compounds may be added in two or more divided portions, or two or more magnesium compounds may be used in combination.

Further, these alkaline earth metal compounds may be used as a transesterification catalyst, but in this case, acetate is preferable. As the amount of such an alkaline earth metal compound added, if it is too small, as a transesterification catalyst, or in scratch resistance, etc., a sufficient effect cannot be obtained, and if it is too large, transparency,
The heat resistance may decrease, so 1 × 10 ^-7 to 1 × 1
Particularly preferably, it is 0 ^-2 mol / g. The alkaline earth metal compound may be added at any time from immediately after the start of the transesterification reaction to immediately before the start of the polymerization reaction, or from after the esterification reaction is substantially completed to immediately before the start of the polymerization reaction. Is preferred, and the addition method is preferably addition as an ethylene glycol solution or an ethylene glycol slurry. These alkaline earth metal compounds may be added in two or more divided portions, or two or more kinds of alkaline earth metal compounds may be used in combination.

The phosphorus compound in the present invention is not particularly limited, but phosphoric acid, phosphorous acid, phosphonic acid, their lower alkyl esters, phenyl esters and the like are preferable. As the addition amount of such a phosphorus compound, if it is too small, sufficient effects cannot be obtained in scratch resistance and the like, and if it is too large, transparency and the like may decrease.
It is particularly preferably 1 × 10 ^{−8 to} 2 × 10 ⁻³ mol / g. Also, as the timing of adding these phosphorus compounds,
It is preferable to add it after the transesterification reaction is substantially completed and immediately before the start of the polymerization reaction. As an addition method, it is preferable to add it as an ethylene glycol solution or an ethylene glycol slurry. These phosphorus compounds may be added dividedly twice or more, or two or more phosphorus compounds may be used in combination.

The addition ratio of the alkali metal compound, the alkaline earth metal compound, and the phosphorus compound in the present invention is 5 ≦ M / P ≦ 500 (I) However, in the formula (I), M: polyester 10 The total number of moles of alkali metal compounds and alkaline earth metal compounds contained per ⁶ g. P: Total number of moles of phosphorus compound contained per 10 ⁶ g of polyester. And 10 ≦ M / P ≦ 30.
It is preferable that 0, especially 30 ≦ M / P ≦ 200.

Further, other compounds may be added in order to improve the functionality such as moldability, transparency and electrostatic castability as long as the effects of the present invention are not impaired. The polyester composition of the present invention preferably contains particles.

The particles (A) in the present invention have an average particle size of 0.005 or more and less than 0.3 μm, and more preferably 0.01-.
It is preferably less than 0.3 μm, particularly preferably 0.05 to 0.2 μm.

The content of the particles (A) in the polymer is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight. If the content is less than 0.01% by weight, abrasion resistance and scratch resistance may not be sufficiently exhibited, and if the content exceeds 10% by weight, agglomeration of particles may occur and coarse particles may be generated. May significantly reduce the surface roughness of the film.

The specific surface area of the particles (A) in the present invention is
It is preferably 10 m ² / g or more, and further 3
It is preferably 0 m ² / g or more, and particularly preferably 100 m ² / g or more.

The type of particles (A) in the present invention is not particularly limited. That is, silicon oxide, titanium oxide, zirconium oxide, aluminum oxide, kaolinite, talc, calcium sulfate, barium sulfate, calcium carbonate,
Inorganic particles such as zinc sulfide, divinylbenzene polymer,
Examples thereof include organic polymer particles such as a styrene-divinylbenzene copolymer and an ethylvinylbenzene-divinylbenzene copolymer. Among these particles, zirconium oxide, aluminum oxide, silicon oxide and titanium oxide are preferable.

Zirconium oxide can be obtained by, for example, firing zirconium oxychloride through zirconium hydroxide, or by subjecting zirconium chloride to gas phase flame hydrolysis, and depending on conditions such as firing temperature, it is amorphous. From the crystal, various crystal systems such as monoclinic crystal, tetragonal crystal, cubic crystal and a mixture thereof can be obtained. In particular, zirconium oxide containing 50% by weight or more of monoclinic crystals obtained by firing zirconium hydroxide is preferable.

Aluminum oxide is, for example, δ-type aluminum oxide when hydrogen and oxygen are blown into aluminum chloride to hydrolyze in the gas phase, and aluminum oxide is amorphous when steam is blown into aluminum chloride to hydrolyze in the gas phase. Aluminum oxide was obtained by the thermal decomposition of alum, and γ-type aluminum oxide was obtained. By neutralizing alum and then thermally decomposing it, θ-type, γ-type and δ-type aluminum oxide were obtained, which were obtained by hydrolyzing aluminum alkoxide. When boehmite is fired, θ type or γ type aluminum oxide is obtained,
Further, by firing gibbsite obtained by spark-discharging aluminum metal pellets in water, η
Type, θ type, and γ type aluminum oxide can be synthesized.

When the activated alumina thus synthesized is fired at a high temperature of 1300 ° C. or higher, α-type aluminum oxide can be obtained. Note that α-type aluminum oxide can be synthesized not only by such a method but also by a method called an ordinary Bayer method.
The determination of such a crystal structure mainly depends on the selection of these synthesis methods and the firing temperature and time.

The particles (A) in the present invention are preferably aluminum oxide particles having one or more kinds of crystal structures selected from the above various kinds of aluminum oxide.

Further, silicon oxide is hydrolyzed by, for example, a dry method in which silicon halide is hydrolyzed at high temperature (flame hydrolysis method), a water glass method in which sodium silicate is directly decomposed by sulfuric acid, or a silicon alkoxide is hydrolyzed. It is manufactured by the alkoxide method or the like. Particles (B) in the present invention
Has an average particle size of 0.3 or more and 2.5 μm or less, and more preferably 0.
It is preferably 3 to 1.5 μm, and particularly preferably 0.4 to 1.0 μm.

The content of the particles (B) in the present invention is 0.
It is preferably 005 to 10% by weight, more preferably 0.05 to 5% by weight. If the content is less than 0.005% by weight, abrasion resistance, scratch resistance, and surface slipperiness may not be sufficiently exhibited, and if the content exceeds 10% by weight, aggregation of particles may occur. May occur, and coarse particles may significantly reduce the surface roughness of the film.

The type of particles (B) in the present invention is not particularly limited. That is, silicon oxide, titanium oxide, zirconium oxide, aluminum oxide, kaolinite, talc, calcium sulfate, barium sulfate, calcium carbonate,
Inorganic particles such as zinc sulfide, divinylbenzene polymer,
Examples thereof include organic polymer particles such as ethylvinylbenzene-divinylbenzene copolymer and styrene-divinylbenzene copolymer. Among these particles, especially calcium carbonate, kaolinite, talc, divinylbenzene polymer, styrene-divinylbenzene copolymer,
Ethyl vinyl benzene-divinyl benzene copolymer and the like are preferable.

Further, such particles (A) and particles (B) may be surface-treated with a surface active agent, a coupling agent, a phosphorus compound or the like, as long as the effects of the present invention are not impaired. .

In blending the particles (A) or particles (B) with the polyester in the present invention, a method of directly kneading the particles into the polyester in a molten state or the like may be used in addition to the method of directly adding to the polymerization reaction system. Is. 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 case of the latter kneading, either a method of drying the particles and kneading into the polyester or a method of directly kneading in a slurry state under reduced pressure may be used. Further, both the particles (A) and the particles (B) may be blended in the same polyester by the method. The polyester composition thus obtained may be used by blending it with a polyester composition such as polyester for dilution depending on the purpose.

The polyester composition of the present invention can be formed into a film by the following method, for example. The pellets of the polyester composition obtained by the polymerization reaction are sufficiently dried and then immediately fed to the extruder. The pellets are melted at 260 to 350 ° C., extruded in a sheet form from a die, cooled on a casting roll and solidified to obtain an unstretched film. Next, this unstretched film is preferably biaxially stretched. As the stretching method, a sequential biaxial stretching method, a simultaneous biaxial stretching method, a method of stretching the biaxially stretched film again, or the like may be used. Although it depends on the composition of the polyester, it is preferable that the final stretched area ratio (longitudinal ratio × lateral ratio) is 6 or more in order to obtain a sufficient elastic modulus as a film for a magnetic recording medium.
In addition, in order to keep the heat shrinkage rate of the film small, 150 to 2
It is preferable to perform heat treatment for about 0.1 to 60 seconds in the temperature range of 60 ° C.

The polyester composition of the present invention is not particularly limited in its use such as general molded products and fibers, but it is particularly preferably used for a film.

The film obtained from the polyester composition of the present invention can be used as a monolayer film or a laminated film. In the case of a laminated film, it is preferable to use the film of the present invention as a film forming at least one layer since the film surface has good abrasion resistance and scratch resistance. Further, from the viewpoint of scratch resistance and dubbing resistance, the film having the particles (A) is preferably one of the outermost layers of the laminated film. As a method for laminating the films, a known method such as melt coextrusion can be used.

The particles (A) and the particles (B) may be contained in the same layer, or may be contained in different layers, but from the viewpoint of scratch resistance and dubbing property, it is particularly preferable. , The particles (A) and the particles (B) are contained in the same outermost layer on at least one side, and the relationship between the film thickness t and the particle diameter d of the particles (B) is 0.2d ≦ t ≦ 10d, Preferably 0.5d ≦ t ≦ 5d, more preferably 0.5
In the case of d ≦ t ≦ 3d, or the relationship between the thickness t of the film layer containing the particles (B) and the particle diameter d of the particles (B) is
0.2d ≦ t ≦ 10d, preferably 0.5d ≦ t ≦ 5
d, more preferably 0.5d ≦ t ≦ 3d, and on the outside thereof, a layer containing the particles (A) is present as an outermost layer, and the thickness of the outermost layer is 0.005 to 1 μm, Preferably 0.01-0.5, more preferably 0.02
It is a case of ~ 0.3.

Further, as in the case of the single film, other particles may be added in order to obtain the slipperiness of the film.

[0033]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. (A) Particle characteristics (1) Average particle size Particles are blended in polyester and cut into 0.2 μm-thick ultrathin sections, and then observed with a transmission electron microscope to find out the number of 1,000 secondary particles in an aggregated state. It was evaluated by the standard circle-equivalent average diameter (μm).

(2) Specific surface area of particles B. E. T. It measured according to the method.

(B) Metal Concentration in Polymer The measurement was carried out by FLX (fluorescent X-ray analysis) and atomic absorption spectroscopy.

(C) Film characteristics (1) Surface roughness Ra (μm) Using a surfcom surface roughness meter according to JIS B-0601, needle diameter 2 μm, load 70 mg, measurement reference length 0.25 m
The center line average roughness measured under the conditions of m and cutoff of 0.08 mm was adopted.

(2) Abrasion resistance A tape-shaped roll in which a film is slit into a narrow width is rubbed against a stainless steel SUS-304 guide roll at a constant tension at high speed for a long time, and the amount of white powder generated on the surface of the guide roll causes Ranked as. Class A: No white powder generated B class: Small amount of white powder C Class: Large amount of white powder D Class: Large amount of white powder generated

(3) Scratch resistance A film slit into a tape having a width of 1/2 inch was run on a guide pin (surface roughness: Ra of 0.1 μm) using a tape running tester. Let (Traveling speed 1,000m / min, number of trips 15 passes, winding angle 60
°, running tension 65g). At this time, the scratches in the film are observed with a microscope, and scratches with a width of 2.5 μm or more per tape width are less than A class, 2 or more and less than 3 are B class, and 3 or more and less than 10 are C. Class 10 or more was D class.

Example 1 10 parts by weight of zirconium oxide particles (particles (A)) having an average particle size of 0.15 μm and 90 parts by weight of ethylene glycol were mixed and stirred at room temperature for 2 hours with a dissolver to obtain zirconium oxide particles. An ethylene glycol slurry (A) was obtained. 10 parts by weight of calcium carbonate particles (particles (B)) having an average particle size of 0.6 μm and ethylene glycol 9
0 part by weight was stirred with a dissolver at room temperature for 2 hours to obtain an ethylene glycol slurry (B) of calcium carbonate particles. 10 parts by weight of magnesium oxide and 90 parts by weight of ethylene glycol were mixed and stirred at room temperature for 2 hours with a dissolver to obtain an ethylene glycol slurry (C) of magnesium oxide. On the other hand, dimethyl terephthalate,
After carrying out transesterification reaction by adding magnesium acetate as a catalyst to eletin glycol, the slurry (A), the slurry (B), the slurry (C), the antimony trioxide as a catalyst, and Trimethyl phosphate was added as a heat resistance stabilizer to carry out polycondensation reaction,
Polyethylene terephthalate was obtained. At this time, the content of metal atoms in the polymer is magnesium atom = 1.3
× 10 ^-4 mol / g, calcium atom = 3 × 10 ^-5 mo
1 / g, phosphorus atom = 1.8 × 10 ⁻⁶ mol / g, M / P
= 88.9. The average particle diameter of the zirconium oxide particles and the average particle diameter of the calcium carbonate particles by a transmission electron microscope were 0.15 μm and 0.6 μm, respectively.

This polyethylene terephthalate composition was melted and extruded at 290 ° C., then stretched at 90 ° C. in the length and width directions by 3 times, and then heat treated at 220 ° C. for 15 seconds to give a polyethylene terephthalate biaxially stretched film having a thickness of 15 μm. Got When this film was evaluated, Ra = 0.021 μm, abrasion resistance evaluation class A, and scratch resistance class A, and the film was very excellent in abrasion resistance and scratch resistance.

Examples 2 to 4 Particle type of particles in polyethylene terephthalate composition,
A biaxially stretched polyester film was obtained in the same manner as in Example 1, except that the average particle size, the addition amount, the addition amounts and types of the alkali metal compound, the alkaline earth metal compound, and the phosphorus compound were changed. Table 1 shows the evaluation results of these films.
It was shown to. It can be seen that these films have good abrasion resistance and scratch resistance.

Example 5 A polyethylene terephthalate composition (X) was obtained in the same manner as in Example 1 except that the particles (A) were not added.
A polyethylene terephthalate composition (Y) was obtained in the same manner as in Example 1 except that the particles (B) were not added.
This (Y) was melt coextruded on (X) to obtain a laminated unstretched film. The extrusion temperature at this time was 290 ° C. Then, the film was stretched at 90 ° C. in the lengthwise and transverse directions by 3 times, respectively, and then heat treated at 220 ° C. for 20 seconds to obtain a laminated biaxially stretched film.

The thickness of each of the layers (X) and (Y) is 8
μm and 0.5 μm. When this film was evaluated, as shown in Table 1, it was Ra = 0.023 μm, abrasion resistance evaluation class A and scratch resistance evaluation class A, and it was a film excellent in abrasion resistance and scratch resistance. It was

Comparative Examples 1-2 Particle type, average particle size, particle content, alkali metal compound,
Amount of alkaline earth metal compound and phosphorus compound added,
A biaxially stretched polyester film was obtained in the same manner as in Example 1 except that the type and the type were changed. The evaluation results of these films are shown in Table 2. These films are abrasion resistant,
The film was not able to satisfy both scratch resistance.

[0045]

[Table 1]

[Table 2]

[0046]

INDUSTRIAL APPLICABILITY The polyester composition of the present invention is excellent in abrasion resistance and scratch resistance, especially when formed into a film, and is suitable for magnetic recording medium applications and the like.

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Claims (4)

[Claims] 1. A polyester composition comprising an amount of an alkali metal compound, at least one compound selected from alkaline earth metal compounds, and a phosphorus compound which satisfy the following general formula (I). 5 ≦ M / P ≦ 500 (I) However, in the formula (I), M: the total number of moles of the alkali metal compound and the alkaline earth metal compound contained per 10 ⁶ g of the polyester. P: Total number of moles of phosphorus compound contained per 10 ⁶ g of polyester. 2. The polyester composition according to claim 1, wherein the magnesium compound is contained in the polyester in an amount of 1 × 10 ⁻⁷ to 1 × 10 ⁻² mol / g. 3. The polyester composition according to claim 1, which contains 0.01 to 10% by weight of particles (A) having an average particle size of 0.005 or more and less than 0.3 μm. 4. The polyester composition according to claim 1, containing 0.005 to 10% by weight of particles (B) having an average particle size of 0.3 or more and 2.5 μm or less.