JP3140856B2 - Method for producing polyester composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester for a magnetic tape, and more particularly, to a method for producing a polyester composition for a magnetic tape, which makes it possible to significantly suppress the aggregation of the fine particles. The present invention relates to a method for producing the composition.

[0002]

2. Description of the Related Art Polyesters, especially polyethylene terephthalate, exhibit excellent physical and chemical properties and are widely used as fibers, films and other molded articles. In addition, various additives are usually added to these compositions according to their uses, and their properties are further improved. When the above-mentioned polyester is used for a magnetic tape film, inorganic or organic fine particles, usually called lubricant particles, are added to the polyester in order to improve the slip characteristics. However, these fine particles have a problem that the smaller the particle size is, the more the aggregation is likely to occur.

[0003]

Therefore, various devices have been devised to solve these problems. For example, a method of surface-treating inorganic inert fine particles with an organic compound (JP-A-49-130448, JP-A-56-269)
No. 58), a method in which a dispersant is added to a slurry in which inorganic or organic fine particles are dispersed, and then this slurry is added to a polymerization system (see JP-A-56-110722 and JP-A-60-139750). ) Are known.
However, even these conventional methods were insufficient to suppress the aggregation of the fine particles in the polyester.

[0004] It is an object of the present invention to provide a method for producing a polyester composition for producing a polyester composition for a magnetic tape, which can significantly suppress the aggregation of fine particles to be blended.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have repeatedly studied the types and amounts of additives and the method of adding the same, and as a result, using a specific additive and a specific amount of the additive. It has been found that the above object can be achieved by adopting the addition method and the addition method, and the present invention has been completed.

That is, the process for producing a polyester composition according to the present invention is characterized in that a polyester comprising a difunctional acid component mainly composed of an aromatic dicarboxylic acid and at least one glycol component has an average particle size of 0.01 to 5%. In preparing a polyester composition containing 0.0 μm inorganic or organic fine particles, before adding the fine particles, an amount of A.P. satisfying the following formulas (1) and (2) is required. At least one salt selected from an alkali metal salt, an alkaline earth metal salt and an ammonium salt; At least one type of phosphorus compound selected from phosphoric acid and a phosphoric acid ester compound is added simultaneously, or the B component is added after the addition of the A component. 1.0≤ (M ⁺ / 2 + M2 ⁺⁺ 3 / 2N3 ⁺ ) / (P1 + P2) ≤2.0 (1) 0.05 <(M ⁺ / 2 + M2 ⁺⁺ 3 / 2N3 ⁺ ) ≤5 (2) (Where M ⁺ is an alkali metal ion in an alkali metal salt, M ²⁺ is an alkaline earth metal ion in an alkaline earth metal salt, and N ³⁺ is 10 ⁶ g of an ammonium ion in an ammonium salt) , And P1 represents phosphoric acid, and P2 represents the total number of moles per 10 ⁶ g of the polyester of the phosphoric ester.)

Hereinafter, the present invention will be described in more detail. As the polyester used in the present invention, known polyesters can be used and are not particularly limited. For example, crystalline polyesters such as polyalkylene terephthalate and polyalkylene naphthalate can be suitably used, and polyalkylene terephthalate is particularly preferable. Also, among the polyalkylene terephthalates, the repeating unit 80
More preferably, at least mol% consists of ethylene terephthalate.

The acid components constituting the polyester include isophthalic acid, p-β-oxyethoxybenzoic acid,
2,6-naphthalenedicarboxylic acid, 4,4-dicarboxylphenyl, 4,4-dicarboxylbenzophenone, bis (4-carboxylphenyl) ethane, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid, cyclohexane-1, A dicarboxylic acid component such as 4-dicarboxylic acid and an oxycarboxylic acid component such as p-oxybenzoic acid are used.

On the other hand, as the glycol component, glycol components such as propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexane dimethanol, an ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol are used. Can be

In the present invention, a desired polyester can be obtained by arbitrarily selecting and using each of the above components and performing polycondensation. In addition, as a copolymer component other than the above components,
A small amount of a compound containing an amide bond, urethane bond, ether bond, carbonate bond or the like can be contained.

The fine particles used in the present invention include dry silica, wet silica, spherical colloidal silica, titanium oxide, calcium oxide, alumina, magnesia, zeolite, kaolin, calcium carbonate, barium sulfate, calcium sulfate, zirconium oxide, Inorganic fine particles such as magnesium carbonate, zinc sulfide, silicon carbide, silicon nitride, aluminum nitride, boron nitride, and talc, and organic fine particles such as silicon resin fine particles, spherical crosslinked acrylic fine particles, and spherical polystyrene fine particles can be used. Use of fine particles and alumina fine particles is effective.

In the present invention, fine particles having an average particle size of 0.01 to 5 μm are preferably used as the fine particles. In particular, when fine particles having an average particle size of 0.5 μm or less are used, the aggregation is effective. It is preferable because it is suppressed. When the average particle size of the fine particles is smaller than 0.01 μm, it is difficult to suppress aggregation. On the other hand, when the average particle size is larger than 5 μm, the aggregation can be suppressed, but the particles are too large. It is not suitable because it is unsuitable as a base film for a magnetic tape. Here, the average particle size is defined as an integrated 50 of the equivalent spherical particle size distribution calculated based on the Stokes equation.
It refers to the diameter at the% point.

In the present invention, in order to satisfy various physical properties required for the magnetic tape, the polyester and the inorganic or organic fine particles are mixed at a ratio of 0.05 to 5 parts by weight of the inorganic or organic fine particles to 100 parts by weight of the polyester. And a composition blended in the above. If the fine particles are less than 0.05 part by weight, the film running property and winding properties become poor when the polyester is formed into a film by a film-forming process. On the other hand, if it exceeds 5 parts by weight, the method according to the present invention may be used. This is not preferable because a considerable amount of aggregation occurs.

In the present invention, when the above composition is prepared,
It is characterized in that at least one salt selected from alkali metal salts, alkaline earth metal salts and ammonium salts is added as the component A, and a phosphorus compound is added as the component B.

Examples of the alkali metal salt of the component A include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium acetate, potassium acetate, lithium acetate, and the like. Particularly, use of sodium hydroxide and sodium acetate is preferable. .

The alkaline earth metal salts include, for example, calcium hydroxide, magnesium hydroxide, calcium oxide, magnesium oxide, calcium acetate, magnesium acetate, calcium chloride, magnesium acetate and the like. Particularly, magnesium acetate, magnesium chloride The use of is preferred.

Examples of the ammonium salt include ammonium sulfate, ammonium chloride, ammonium bromide, ammonium salts of polyacrylic acid or polymethacrylic acid, and copolymers thereof.

On the other hand, as the phosphorus compound of the component B,
Phosphoric acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, triphenyl phosphate, monophenyl phosphate, dimethyl phosphate, dimethyl phosphate, monobutyl phosphate, dibutyl phosphate, etc. They may be used alone or in combination of two or more. Of these, phosphoric acid and trimethyl phosphate are particularly preferred.

In the present invention, it is important that the amounts of the components A and B added satisfy the following formulas (1) and (2). 1.0≤ (M ⁺ / 2 + M2 ⁺⁺ 3 / 2N3 ⁺ ) / (P1 + P2) ≤2.0 (1) 0.05 <(M ⁺ / 2 + M2 ⁺⁺ 3 / 2N3 ⁺ ) ≤5 (2) (Where M ⁺ is an alkali metal ion in an alkali metal salt, M ²⁺ is an alkaline earth metal ion in an alkaline earth metal salt, and N ³⁺ is 10 ⁶ g of an ammonium ion in an ammonium salt) , And P1 represents phosphoric acid, and P2 represents the total number of moles per 10 ⁶ g of the polyester of the phosphoric ester.)

The component A is used in an amount that satisfies the above formula (2). When the addition amount of the component A is out of the above range,
It is not preferable because the effect of preventing aggregation is not exhibited or the component A precipitates. Generally, when the component A is added in an amount of 0.001 to 0.1 part by weight, particularly 0.005 to 0.05 part by weight, based on 100 parts by weight of the polyester composition, the above formula (2) is satisfied. And a good coagulation preventing effect can be obtained.

The addition amount of the component B varies depending on the amount of the component A, but an amount that satisfies the above formula (1) is used. If it is out of the above range, it becomes difficult to exhibit a good aggregation preventing effect, or a foreign substance occurs in the polymer,
It is not preferable because additives are deposited or important electrostatic adhesion is not obtained during film formation.

In the present invention, it is important that the addition of the components A and B is completed before the addition of the fine particles, and it is particularly preferable before the esterification reaction in the preparation of the polyester. When the addition time is after the addition of the fine particles, it becomes very difficult to exhibit a desired aggregation suppressing effect. It is desirable that the component A be added as much as possible before the initial polymerization. On the other hand, the component B is added all at once or dividedly. The addition of the component A and the component B is carried out by adding the component A and the component B simultaneously, or by adding the component B after the addition of the component A. In particular, it is more preferable to add the component B after adding the component A.

[0023]

The polyester composition containing inorganic or organic fine particles produced by such a method has a significantly improved degree of aggregation of the fine particles, and a base film for a time tape was formed using these. In this case, it is possible to obtain a base film having very few dropouts which are disadvantages of the film.

[0024]

Next, Examples and Comparative Examples of the present invention will be described.
The present invention is not limited to the following examples. In the examples, all parts are by weight unless otherwise specified. The measurement method and the determination method used in the following examples and comparative examples are as follows.

(1) Average particle size: Centrifugal sedimentation type particle size distribution analyzer (SA-
From the equivalent spherical distribution obtained by CP-3), an integration of 50%
The value at the time of was expressed.

(2) Number of coarse particles of polymer A small amount of polymer is sandwiched between two cover glasses, and
After melt-pressing at ℃ and cooling, observation was performed using a phase-contrast microscope, and the number of particles having a maximum length of 5 μm or more in the image was counted using an image analysis processor Luzex 500 (manufactured by Nippon Regulator). However, excellent: the number of coarse projections of 5 μ or more and less than 15 was obtained. Good: The number of coarse projections of 5 μ or more is 15 or more and less than 40. Acceptable: Those having the number of coarse protrusions of 5 μ or more and less than 100. Impossible: 100 or more coarse protrusions of 5 μ or more. Was evaluated.

(3) Melt Specific Resistance Two electrode plates were placed in polyester melted at 275 ° C., and a current value (iO) when a voltage of 120 V was applied was measured, and this current value was applied to the following equation. , Specific resistance (ρ
i) was determined. Here, ρi (Ω · cm) = (A / 1) × (V / iO) A = electrode area (cm ² ), 1 = distance between electrodes, V = voltage (V) Evaluation: good: specific resistance value ( ρi) less than 0.3. Acceptable: Those having a specific resistance value (ρi) of 0.3 or more and less than 0.45. Impossible: Specific resistance value (ρi) is 0.45 or more. Was determined. The value of the melting specific resistance is used as a criterion for judging the adhesion between the casting roll and the original width at the time of forming the polyester film, and the alkali metal and / or alkaline earth contained in the polyester is used. It depends on the amount of metal and the ratio of this amount to the amount of phosphorus, and the smaller the value, the better the adhesion.

Example 1 1.48 parts by weight of calcium carbonate particles having an average particle size of 0.5 μm (manufactured by Maruo Calcium Co., Ltd.);
8 parts by weight and 0.00296 parts by weight of 0.1 mol / l sodium tripolyphosphate were mixed and stirred with a homogenizer to obtain 16.3 parts by weight of a slurry. On the other hand, 100 parts by weight of terephthalic acid and 70.7 ethylene glycol
Then, 0.0697 parts by weight of antimony trioxide, 0.271 parts by weight of triethylamine and 0.0931 parts by weight of magnesium acetate were added, and pressure esterification was performed at a pressure of 2.5 kg / cm ² and a temperature of 250 ° C. Then, 0.0327 parts by weight of trimethyl phosphate was added,
Stirring was performed at normal pressure of 60 ° C., and after 30 minutes, 11.0 parts by weight of the previously prepared slurry was added, and the mixture was further stirred for 30 minutes. Thereafter, a polycondensation reaction is carried out under vacuum (η) 0.1.
Thus, a polyethylene terephthalate composition of No. 62 was obtained. As a result of evaluating the number of coarse particles and the melting specific resistance of the obtained polymer, it was as shown in Table 1.

Example 2 In the same manner as in Example 1, a slurry of calcium carbonate particles having an average particle size of 0.5 μm was obtained. On the other hand, terephthalic acid 100
Parts by weight, 70.7 parts by weight of ethylene glycol, 0.0697 parts by weight of antimony trioxide, 0.271 parts by weight of triethylamine, 0.032 parts of trimethyl phosphate
7 parts by weight and 0.0931 parts by weight of magnesium acetate were added thereto, and pressure esterification was performed at a pressure of 2.5 kg / cm ² and a temperature of 250 ° C. After completion of the pressure esterification, 11.0 parts by weight of the slurry prepared above was added, and the mixture was stirred at 260 ° C. for 30 minutes under normal pressure. Thereafter, a polycondensation reaction was carried out at 280 ° C. under vacuum to obtain a polyethylene terephthalate composition of (η) 0.62. As a result of evaluating the number of coarse particles and the melting specific resistance of the obtained polymer, it was as shown in Table 1.

Examples 3 to 7 and Comparative Examples 1 to 4 The polyethylene terephthalate composition was prepared in the same manner as in Example 1 except that the types, amounts and proportions of the added components were changed as shown in Table 1. Obtained. As a result of evaluating the number of coarse particles and the melting specific resistance of each of the obtained polymers, the results are as shown in Table 1.

Examples 8 to 9 Polyethylene terephthalate compositions were obtained in the same manner as in Example 1, except that calcium carbonate was changed to one having an average particle size shown in Table 1. As a result of evaluating the number of coarse particles and the melting specific resistance of the obtained polymer, it was as shown in Table 1.

Comparative Example 5 1.48 parts by weight of calcium carbonate particles having an average particle size of 0.5 μm (manufactured by Maruo Calcium Co., Ltd.);
8 parts by weight and 0.00296 parts by weight of 0.1 mol / l sodium tripolyphosphate were mixed and stirred with a homogenizer to obtain 16.3 parts by weight of a slurry. On the other hand, 100 parts by weight of terephthalic acid and 70.7 ethylene glycol
Then, 0.0697 parts by weight of antimony trioxide, 0.271 parts by weight of triethylamine and 0.0931 parts by weight of magnesium acetate were added, and pressure esterification was performed at a pressure of 2.5 kg / cm ² and a temperature of 250 ° C. After completion of the pressure esterification, 11.0 parts by weight of the slurry prepared above was added,
After stirring at 260 ° C. under normal pressure for 30 minutes, 0.0327 parts by weight of trimethyl phosphate was added, and the mixture was further stirred for 30 minutes. Thereafter, a polycondensation reaction is performed under vacuum (η).
A polyethylene terephthalate composition of 0.62 was obtained.
As a result of evaluating the number of coarse particles and the melting specific resistance of the obtained polymer, it was as shown in Table 1.

[0033]

[Table 1]

As is clear from the above table, all of the polyester compositions obtained in the examples were excellent in that the number of coarse particles of the polymer was less than 40, which was good or better. Further, the melting specific resistances were all appraisable or higher, which were less than 0.45, and were usable.

[0035]

As described above in detail, according to the present invention, a polyester composition in which the degree of aggregation of fine particles is greatly improved can be obtained. Obtainable. Therefore, it is possible to stably produce a polyester composition most suitable for a base film for a magnetic tape.

Continuation of the front page (56) References JP-A-60-139750 (JP, A) JP-A-56-110722 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 67 / 00-67/03

Claims (1)

(57) [Claims] An inorganic or organic fine particle having an average particle size of 0.01 to 5.0 μ is blended with a polyester comprising a bifunctional acid component mainly composed of an aromatic dicarboxylic acid and at least one glycol component. When the polyester composition is produced, before the fine particles are added, an amount of A.P. satisfying the following formulas (1) and (2) is used. At least one salt selected from an alkali metal salt, an alkaline earth metal salt and an ammonium salt; A method for producing a polyester composition, comprising simultaneously adding at least one type of phosphorus compound selected from phosphoric acid and a phosphoric acid ester compound, or adding the component B after the addition of the component A. 1.0≤ (M ⁺ / 2 + M2 ⁺⁺ 3 / 2N3 ⁺ ) / (P1 + P2) ≤2.0 (1) 0.05 <(M ⁺ / 2 + M2 ⁺⁺ 3 / 2N3 ⁺ ) ≤5 (2) (Where M ⁺ is an alkali metal ion in an alkali metal salt, M ²⁺ is an alkaline earth metal ion in an alkaline earth metal salt, and N ³⁺ is 10 ⁶ g of an ammonium ion in an ammonium salt) , And P1 represents phosphoric acid, and P2 represents the total number of moles per 10 ⁶ g of the polyester of the phosphoric ester.)