JPH02117950A - Polyester and production thereof - Google Patents

Abstract

PURPOSE:To obtain a polyester excellent in transparency and lubricity by incorpolating tungsten trioxide granules of specified mean size during the production process for the polyester. CONSTITUTION:When a polyester is to be produced by eater interchange or esterification reaction between terephthalic acid or its ester-forming derivative and glycol followed by polycondensation, an ethylene glycol slurry of tungsten trioxide granules 0.01-5 (pref. 0.05-2) mu in mean size at 1-50wt.% concentration is added to the system prior to the completion of the polycondensation so as to be 0.001-5wt.% in the content of said granules in the final polyester.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application gf] The present invention relates to a polyester with excellent transparency and slipperiness, and a method for producing the same.

[Prior Art] Polyesters produced industrially today, such as polyesters whose main constituent unit is polyethylene terephthalate, have excellent physical and chemical properties, and are suitable for fibers,
Widely used in films and other molded products. In film applications, the most basic required properties are transparency and slipperiness. A method is known in which inorganic particles such as calcium carbonate, kaolin, and silicon trioxide, which are inert to polyester, are present in the polymer as a slipperiness improver.

However, if these particles are blended to impart sufficient slipperiness, transparency will be impaired, whereas slipperiness cannot be obtained if the amount added does not impair transparency.

For this reason, JP-A-54-57562 describes a method of improving lubricity and transparency by adding a specific amount of calcined kaolin particles of a specific particle size. However, since kaolin particles are used by crushing natural products, the contamination of coarse particles is unavoidable, making it impossible to obtain a homogeneous product. Furthermore, it is known from JP-A-54-139653 that smoothness and transparency can be achieved by adsorbing a specific silicone compound onto inert inorganic particles and blending it into polyester to reduce the amount of particles added. . However, the relationship between slipperiness and transparency of films obtained using these methods is still unclear.
It is hoped that a better film will emerge.

As a result of repeated studies on how to improve the shortcomings of these conventional techniques, the inventors of the present invention found that by blending tungsten trioxide particles with a specific particle size, for example, polyester can be made into a film with extremely good slipperiness and transparency. This is what we have discovered and arrived at the present invention.

[Problems to be Solved by the Invention] An object of the present invention is to provide a polyester and a method for producing the same that can satisfy the slipperiness and transparency of a polyester film that could not be achieved using conventional techniques.

[Means for Solving the Problems] The above-mentioned objects of the present invention can be achieved by a polyester whose main constituent unit is ethylene terephthalate and which contains tungsten trioxide particles having an average particle size of 0.01 to 5 μm.

The polyester in the present invention is mainly composed of polyethylene terephthalate, which can be molded into fibers, films, and other molded products.

Of course, these polyesters may be copolyesters, and examples of copolymerizable components include diethylene glycol, propylene glycol, polyalkylene glycol, p=xylylene glycol, 1,4-cyclohexane dimetatool, and 5-sodium sulfonate. Diol components such as resorcinol, dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, and 5-sodium isophthalic acid, and polyfunctional dicarboxylic acids such as trimellitic acid and pyromellitic acid. component, and oxycarboxylic acid components such as p-oxyethoxybenzoic acid.

The polyester in the present invention has an average particle size of 0°01 to 5μ
tungsten trioxide particles. Here, the average particle diameter is the equivalent spherical diameter J (E, S, D: E
quivalent Spherical Diamet
er), which refers to the diameter of an imaginary sphere with the same volume as the particle, and can be calculated from electron micrographs of the particles or measurements by conventional sedimentation methods.

In addition, the shape of the particles is preferably spherical from the viewpoint of slipperiness, and preferably has a volume shape coefficient of 0.30 to 0.52μ,
More preferably, it is 0.4 or more.

[However, the volumetric shape factor f is expressed by the following equation.

■ f = − ■ = Particle volume (μm3) D- Maximum diameter of particle in projected plane (μm>) The average particle size of tungsten trioxide particles in the present invention is 0.01 to 5
．． 0μ is used, preferably 0.05 to 3
．． It is 0μ, more preferably 0.05 to 2.0μ. If the particle size is less than 0.01μ, the effect on slipperiness will be insufficient. Further, when the average particle size exceeds 5 μm, voids occur, and transparency of the film decreases due to increased scattering on the film surface caused by coarse protrusions.

For example, when used as a film, the particle content is preferably 0.001 to 5 from the viewpoint of slipperiness and transparency.
．． 0% by weight, more preferably 0.005-2.0
It is preferably 0.01 to 1.0% by weight, more preferably 0.01 to 1.0% by weight.

Furthermore, dyes, pigments, nucleating agents, and other additives may be added to the polyester of the present invention as desired, depending on the purpose.

Specifically, the polyester of the present invention is produced by performing a transesterification or esterification reaction between terephthalic acid or an ester-forming derivative and a glycol, followed by a polycondensation reaction to produce polyester.
It can be produced by adding an ethylene glycol slurry of tungsten trioxide particles of 1~5°0μ to a polyester production reaction system.

More specifically, for example, when a dicarboxylic acid mainly consisting of terephthalic acid is used as a starting material, terephthalic acid and glycol are esterified, and when the dicarboxylic acid component is an ester of terephthalic acid, it is transesterified with glycol. Thereafter, the obtained prepolymer is subjected to polycondensation at high temperature under vacuum to obtain a polyester. It is also possible to polycondensate using the prepolymer itself as a starting material.

The tungsten trioxide particles referred to in the present invention may be commercially available high-purity products with a desired nominal particle size, or any raw powder may be prepared in a wet state by natural sedimentation, centrifugation,
The particle size may be adjusted to an average particle size in the range of 0.01 to 5.0 μm using cyclone separation in a dry state, bag filter separation method, or the like.

Tungsten trioxide particles may be added before the completion of polycondensation; for example, they can be added at any stage of esterification, transesterification, or polymerization, but it is preferable to add them before the start of polymerization. preferable.

The average particle size of the tungsten trioxide particles used in the present invention is 0.
．． 0.01 to 5.0 μm is used, preferably 0.01 μm to 5.0 μm.
05-3.0μ, more preferably 0.05-2.0μ. If the particle size is less than 0°01μ, the effect on slipperiness will be insufficient. If the average particle size exceeds 5 μm, the transparency of the film decreases due to the generation of voids and increased scattering on the film surface due to coarse protrusions.

From the viewpoint of transparency and slipperiness, the amount added is preferably 0.
001 to 5.0% by weight, more preferably 0.00%
It is 5 to 2.0% by weight, more preferably 0.01 to 180% by weight.

In addition, the form of the tungsten trioxide particles to be added is that ethylene glycol is used as a slurry medium, but small amounts of other components such as water and organic solvents such as methanol may also be included, and surfactants, acids, alkalis, etc. A small amount of a pH adjuster or the like may be used in combination depending on the purpose. As the stirring/mixing method, conventionally known means such as a homomixer, a high-speed stirrer, and ultrasonic dispersion may be used, or a combination of these methods may be used. The concentration of tungsten trioxide particles in the ethylene glycol slurry is preferably 1 to 50% by weight, more preferably 5 to 20% by weight.

[Example] Next, the present invention will be specifically explained with reference to Examples.

In addition, the measurement of each characteristic value of polyester was performed according to the following method.

(A) Particle Size The average particle size was determined from the equivalent spherical diameter of particles at an addition amount of 50% by weight of the total particles, as measured by electron micrographs of the particles. The equivalent spherical diameter is the diameter of a sphere with the same volume as the particle.

(B) Film haze, film friction coefficient Film haze was measured according to ASTM-D 1003-52 method.

The coefficient of friction of the film was measured using a slip tester manufactured by Toyo Tester Co., Ltd. according to the ASTM-D-1894B method, and the coefficient of static friction (μS) was used as a measure of slipperiness.

The haze of the film is 2.0% or less, and the coefficient of static friction (
μS) of 1.5 or less is within the scope of the present invention as a raw material for a transparent, easily slippery film.

(C) Intrinsic viscosity of polyester Measurement was performed at 25°C using 0-chlorophenol as a solvent.

Example 1 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 0.10 parts by weight of calcium acetate as a transesterification catalyst, and 0.03 parts by weight of antimony trioxide as a polycondensation catalyst were added to the theoretical amount at 140 to 220°C. methanol was distilled off to complete the transesterification reaction.

Next, 1 portion of an ethylene glycol slurry containing 0.04 parts by weight of trimethyl phosphate and 5% by weight of tungsten trioxide with an average particle size of 0.4μ and a volume shape coefficient of 0°48 was added to the system.
,0 parts by weight were added. Then, gradually reduce the pressure in the system 1
Ethylene glycol was distilled out at a temperature of 290° C. under a reduced pressure of mm Hg, and the reaction was completed in 4 hours.

The intrinsic viscosity of the obtained polyethylene terephthalate was 0.
It was 605. This polymer was made into chips, dried, and made into a sheet using an extruder at 290 to 300°C.
The film was biaxially stretched at 00°C to obtain a 25μ film. As a result of evaluating the film properties, it was found that the film had good slipperiness and transparency. (Table 1) Comparative Example 1 In the production of the polyester film of Example 1, the average particle size of tungsten trioxide was outside the range of the present invention.
Polyester and film were produced in the same manner by adding 0μ.

As shown in Table 1, although the slip properties were good, the transparency was not satisfactory.

Example 2 The same procedure as Example 1 was carried out except that tungsten trioxide with various average particle diameters and amounts added was used. When a film was made using tungsten trioxide with an average particle size of 0°8μ, which is within the range of the present invention, it had excellent transparency and slipperiness, as in Example 1. (Experiment Nα2.3) Similarly, when a film was made using tungsten trioxide with an average particle size of 1.5 μm, both transparency and slipperiness were good. (Experiment No. 4) Example 3 1.4 times the mole of ethylene glycol was added to 100 parts by weight of terephthalic acid, and 0.007 parts by weight of monobutyltin oxide and 0.03 parts by weight of antimony trioxide were added as catalysts. The esterification reaction was carried out while heating the mixture to 240°C under a pressure of 4 g/min and continuously distilling the produced water out of the system, and the reaction was completed 6 hours after the start of the reaction.

Subsequently, 0.005 parts by weight of trimethyl phosphate and 1.0 parts by weight of tungsten trioxide having an average particle size of 0°4μ and a volume shape factor of 0.48, which was made into an ethylene glycol slurry with a concentration of 10% by weight, were added to the obtained product. did. Next, the pressure inside the system was gradually reduced to 290°C under a reduced pressure of 1.0 mmHg.
Ethylene glycol was distilled out at a temperature of 100 ml, and the reaction was completed in 3 hours.

The intrinsic viscosity of the obtained polyethylene terephthalate was 0.
It was 610. This polymer was made into a film in the same manner as in Example 1.

As shown in Table 1, the film properties were excellent in both slipperiness and transparency. 9 Comparative Example 2 In place of tungsten trioxide in Example 1, colloidal silica particles, titanium trioxide particles, α- The same procedure as in Example 1 was carried out except that alumina particles were used.

When colloidal silica with an average particle size of 1.0 μm is used as an additive, the slipperiness is satisfactory, but the transparency is poor. (Experiment N (17)) Furthermore, when titanium trioxide with an average particle size of 0.3 μm or α-alumina with an average particle size of 0.8 μm is used, both slipperiness and transparency are inferior to those of the Examples. (Experiment N (18, 9) (Hereinafter, blank) [Effects of the invention] Since the polyester of the present invention contains tungsten trioxide particles with an average particle size of 0.01 to 5μ, fibers obtained from this polyester The film or molded product has excellent slipperiness and good transparency.In addition, tungsten trioxide particles are well dispersed, so when made into a film, for example, operations such as winding and storage are easy. Also, clogging of the molding machine during extrusion, etc.
No problems such as thread breakage occur.

Claims (2)

[Claims] (1) A polyester whose main constituent unit is ethylene terephthalate, which contains tungsten trioxide particles with an average particle size of 0.01 to 5 μm. (2) When producing polyester by transesterifying or esterifying terephthalic acid or an ester-forming derivative and a glycol, and subsequently carrying out a polycondensation reaction, the average particle size is 0.01 to 5.
A method for producing polyester, characterized in that an ethylene glycol slurry of μ tungsten trioxide particles is added.