JP3131980B2 - Thermoplastic polyester composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermoplastic polyester composition. More specifically, the present invention relates to a thermoplastic polyester composition in which agglomerated amorphous alumina particles are blended with a thermoplastic polyester to provide excellent abrasion resistance. The present invention relates to a thermoplastic polyester composition suitable for obtaining a cured film or fiber.

[Prior Art] In general, thermoplastic polyesters such as polyethylene terephthalate have excellent mechanical properties and are widely used as molded articles such as films and fibers. Usually, in order to impart lubricity to a molded article, the polyester is made to contain inert particles in the polyester, and a method of imparting irregularities to the surface of the molded article is performed. Although there are various types of such inert particles, generally, the inert particles have a problem that they lack affinity for the polyester and are inferior in abrasion resistance.

Conventionally, surface treatments have been studied to solve this problem. For example, JP-A-63-221158 and JP-A-
JP-A-63-280763 (modifying the surface of colloidal silica particles with a glycol group), JP-A-63-312345 (modifying the surface of colloidal silica particles with a coupling agent), and JP-A-62-235353 JP-A No. (the surface treatment of calcium carbonate particles with a phosphorus compound) has been proposed.

However, even in the case of using such a known method, when particles are repeatedly used by friction like a magnetic tape, the particles also fall off. For this reason, the use of special particles has recently been proposed. For example, JP-A-62-172031 (silicon particles) and JP-A-2-1292
No. 30 (delta-type aluminum oxide particles) has been proposed, but is still insufficient.

[Problems to be Solved by the Invention] An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and in particular, by blending agglomerated amorphous alumina particles with a thermoplastic polyester, to achieve excellent abrasion resistance. An object of the present invention is to obtain a polyester composition capable of producing films and fibers.

[Means for Solving the Problems] The object of the present invention is to provide a thermoplastic polyester composition containing agglomerated amorphous alumina particles having a specific surface area of primary particles measured by a BET method of 50 m ² / g or more. Can be achieved by:

The agglomerated amorphous alumina particles in the present invention mean agglomerates of amorphous alumina particles by X-ray diffraction. FIG. 1 is an X-ray diffraction diagram of the amorphous alumina particles, but a unique crystal peak as observed in α, δ, and γ type alumina particles is not observed. There are various synthetic methods for the alumina particles, and the crystal structure can be determined by them. For example, when hydrogen and oxygen are blown into aluminum chloride and hydrolyzed in the gas phase, δ-type alumina is obtained. In alum thermal decomposition, γ-type alumina is obtained. Can be. Also,
In a method called a usual via method, α-type alumina is produced. Although there are various methods for synthesizing amorphous alumina, in view of the dispersibility of particles, a synthesis method in which water vapor is blown into aluminum chloride to hydrolyze in the gas phase is preferable.

Other various production methods can be cited, but the amorphous alumina used in the present application contains a large amount of crystal water taken out at the stage where the calcination time is short or the calcination temperature is low in the production process of various crystalline aluminas. , A so-called hydrated alumina.

Among these aluminas having various crystal structures, in particular, when amorphous alumina is blended with polyester, it becomes very excellent in abrasion resistance when formed into fibers or films. Although the reason for this is unknown, it is thought that the amorphous one has a stronger interaction with the polyester in the polyester, and as a result, the affinity is improved.

The primary particle diameter is extremely difficult to measure because of the extremely fine particles, and is represented by the specific surface area. This specific surface area is 50 m ² / g or more as measured by the BET method. Naturally, such particles cause agglomeration in the polyester, but the secondary particle size can be arbitrarily selected according to the purpose of the molded article made of the thermoplastic polyester composition. When used for films or fibers, if too large, coarse projections are formed on the molded article, preferably 5.0 μm or less, more preferably 3.0 μm
m or less. It is preferable that the thickness be 0.01 μm or more.

Here, the secondary particle diameter is an average diameter equivalent to a circle when 1,000 particles are observed with a transmission electron microscope.

Further, the addition amount of the coagulated amorphous alumina particles is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 20 parts by weight, based on 100 parts by weight of the thermoplastic polyester.

The thermoplastic polyester in the present invention is produced by a polycondensation reaction using a bifunctional component such as an aromatic dicarboxylic acid or a dialkyl ester thereof and a glucose component as raw materials. In particular, those mainly composed of polyethylene terephthalate are preferred. The polyester may be a homopolyester or a copolyester, and examples of copolymerization include adipic acid, sebacic acid, phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, and 5-sodium sulfoisophthalic acid. A dicarboxylic acid component such as an acid, a polyvalent carboxylic acid component such as trimellitic acid and pyromellitic acid, and tetramethylene glyco-
, Hexamethylene glycol, diethylene glycol
, Prorelylene glycol, neopentyl glycol,
Examples include diol components such as polyoxyalkylene glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, and 5-sodium sulforesorcin.

The polyester composition of the present invention is, for example, a production method in which amorphous alumina particles are mixed and stirred with a glycol solvent, which is a starting material of the intended polyester, to form a dispersion slurry, which is added to a thermoplastic polyester reaction system. And so on. In this case, the processing method may be, for example, an ultrasonic wave or the like without using stirring, or a medium type mill such as a sand grinder may be used.
For the incorporation into the polyester, in addition to the above-mentioned method of directly adding to the polymerization reaction system, for example, a method of kneading amorphous alumina particles into a molten polyester is also possible. The timing of the addition to the former polymerization reaction system is arbitrary, but is preferably from before the transesterification reaction to before the start of the pressure reduction in the polycondensation reaction. In the case of the latter kneading, a method of drying and kneading the particles into the polyester or a method of directly kneading while reducing the pressure in a slurry state may be used. In consideration of dispersibility, it is preferable to directly knead the mixture in a kneader having a high shearing force while reducing the pressure in a slurry state.

[Examples] Next, the present invention will be specifically described with reference to Examples and Comparative Examples.

(1) Evaluation of specific surface area of agglomerated amorphous alumina particles Measured (m ² / g) according to a usual BET method.

(2) Evaluation of Secondary Particle Diameter of Aggregated Amorphous Alumina Particles
After cutting into a 2 μm-thick ultrathin section, it was observed with a transmission electron microscope, and evaluated by the area average diameter (μm) of 1000 aggregated secondary particles.

(3) Evaluation of abrasion resistance The obtained polyester composition was formed into a biaxially stretched film by the method shown in the examples, and a tape-shaped raw material slit into a narrow width.
The roller was rubbed against a stainless steel SUS-304 guide roll with constant tension at a high speed for a long time, and ranked according to the amount of white powder generated on the surface of the guide roll as follows.

First class: No white powder is generated. Second class: White powder is slightly generated. Third class: White powder is generated considerably. (4) Evaluation of surface unevenness. A biaxially stretched film is formed by a normal method, using a Surfcom surface roughness meter in accordance with JISB0601, a center line average roughness under the conditions of a needle diameter of 2 μm, a load of 70 mg, a measurement reference length of 0.25 mm, and a cutoff of 0.08 mm ( Ra) was measured.

(5) Production of Amorphous Alumina Amorphous alumina having a different specific surface area was produced by blowing steam into aluminum chloride gas and changing the conditions for blowing steam.

Example 1 About 50 g of gas obtained by evaporating aluminum chloride at about 140 ° C.
At a flow rate of 20 g / min, the mixture is blown into a conduit controlled at 110 ° C. to hydrolyze and remove excess water, and a BET specific surface area of 125 m ² /
g of amorphous alumina was obtained. 10 parts by weight of the agglomerated amorphous alumina particles (the X-ray diffraction chart is shown in FIG. 1) and 90 parts by weight of ethylene glycol were mixed and stirred at room temperature for 1 hour with a turbine blade to obtain an amorphous Alumina particles / ethylene glycol slurry (A) was obtained.

On the other hand, dimethyl terephthalate (100 parts by weight) and ethylene glycol (64 parts by weight) were mixed with
After the transesterification reaction was performed, 5 parts by weight of the slurry (A) prepared above, 0.03 part by weight of antimony oxide as a catalyst, and 0.03 part by weight of trimethyl phosphate as a heat stabilizer were added to the reaction product. To perform a polycondensation reaction,
A polyethylene terephthalate composition having an intrinsic viscosity of 0.616 was obtained. Secondary particle size by transmission electron microscope is 0.15μm
Met. This polyethylene terephthalate composition was treated with 29
Extruded at 0 ° C, stretched 3 times each in length and width at 90 ° C, and then burned at 220 ° C for 15 seconds, thickness 15μ
m of polyethylene terephthalate biaxially stretched film.

When this film was evaluated, it was Ra = 0.010 μm, and the wear resistance was evaluated as first class. The film was very excellent in wear resistance.

Examples 2 to 5 In the same manner as in Example 1 except that the amount of steam blown was 30 g / min and 10 g / min, the BET specific surface area was 138 m ² / min.
g, 105 m ² / g particles, BET specific surface area in the same manner as in Example 1 except that the temperature of the conduit is 120 ° C. and 130 ° C.
Particles of 111 m ² / g and 89 m ² / g were obtained. Using these particles, the specific surface area, secondary particle size, amount of addition, etc. of the coagulated amorphous alumina particles in the polyethylene terephthalate composition were changed, and the biaxially stretched polyester was produced in the same manner as in Example 1. A film was obtained. The evaluation results of these films are shown in Table 1, and the films were very excellent in abrasion resistance.

Comparative Examples 1-5 The type of particles and the crystal structure of alumina particles were changed,
A biaxially stretched polyester film was obtained in the same manner as in Example 1. The evaluation results of these films are shown in Table 2, but the films were not satisfactory in abrasion resistance.

[Effect of the Invention] The polyester composition obtained by mixing the agglomerated amorphous alumina particles in the polyester composition of the present invention with polyester has good abrasion resistance when molded into fibers, films, or the like. Therefore, the polyester composition of the present invention is effective for fibers, films or other molded products, but can be preferably used for magnetic tapes which are used repeatedly by friction.

[Brief description of the drawings]

 FIG. 1 is an X-ray diffraction diagram of the amorphous alumina particles.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08J 5/18 C08L 67/00-67/04

Claims (1)

(57) [Claims] 1. A thermoplastic polyester composition containing agglomerated amorphous alumina particles having a specific surface area of primary particles of at least 50 m ² / g as measured by the BET method.