JPS6337816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyester, in particular,
The present invention relates to a method for producing polyester, which has excellent slipperiness and has few defects such as knobs and fish eyes, and is suitable as a raw material for producing fibers, films, and the like.

Since polyester has excellent mechanical, electrical, and thermal properties, it is widely used as a raw material for various materials such as fibers and films. However, fibers and films obtained from polyester containing polyalkylene terephthalate as a main component already have a high coefficient of friction and are difficult to pass through the process during spinning or film forming. There is a strong desire to establish a method for producing polyester that can form a film.

In general, a method for improving the slipperiness of polyester fibers or films is to mix insoluble fine particles with polyester to form fine irregularities on the surface of the fibers or films. The so-called external particle method involves adding inactive fine particles to polyester such as titanium dioxide, kaolinite, talc, and silica during the production of polyester, and the so-called external particle method in which inert fine particles such as titanium dioxide, kaolinite, talc, and silica are added to polyester, and the addition of carboxylic acid components, oligomers, or phosphorus compounds during the polyester production reaction. There is a so-called internal particle method in which fine particles are formed by reacting the metal compound with a metal compound. When the external particle method and the internal particle method are compared, the internal particle method is said to be more advantageous for the following reasons.

It is economically advantageous because it does not require equipment for particle refinement, classification, and dispersion.

In the external particle method, it is necessary to use a dispersant in order to prevent knobs and eyes due to agglomeration of the added fine particles, but in the internal particle method, this is not necessary. Generally, dispersants impede the heat resistance and electrical properties of the product, so it is best not to add them.

Particles produced by the internal particle method generally have low hardness, so products with excellent wear resistance can be obtained.

Particles produced by the internal particle method have good compatibility with polyester, so no voids occur even when stretched, and since they have a refractive index close to that of polyester, the product has high transparency.

By the way, in the internal particle method, fine particles are formed using catalyst residues of alkali metals, alkaline earth metals, etc. used as transesterification catalysts, and the amount and particle size of the fine particles formed are adjusted by adding a phosphorus compound. The method of doing so is the mainstream. However, this method has the following problems and cannot be said to satisfy market demands.

Coarse particles tend to form, often resulting in products with low transparency. Moreover, coarse particles cause product defects such as fiber knobs and film fixation eyes.

Scale tends to form inside the polymerization can, which sometimes falls off and gets mixed into the polyester, causing defects such as knobs and fixing eyes.

Polymerization conditions must be strictly controlled in order to keep the amount and particle size of fine particles constant at all times.

The present inventor focused on the above-mentioned circumstances, and completed as a result of intensive research to establish a method for producing polyester that has excellent transparency and slipperiness and has fewer product defects such as knobs and fitting eyes. Its composition consists of terephthalic acid or its ester-forming derivative (hereinafter sometimes referred to as acid component) and alkylene glycol in the presence of at least one polycondensation catalyst selected from the group consisting of titanium compounds and germanium compounds. In producing polyester, from the start of the reaction until the intrinsic viscosity of the reactant reaches 0.2 due to the progress of the polycondensation reaction,
Add a zirconium compound soluble in the reaction system to the polyester produced in an amount of 80 to 80% in terms of zirconium atoms.
There is a gist in adding 2500ppm.

The polyester of the present invention has 80 repeating units.
More than mol% is composed of alkylene terephthalate, and other copolymerized components include isophthalic acid, P-β-oxyethoxybenzoic acid, 2,6-
Naphthalenedicarboxylic acid, 4,4'-dicarboxyldiphenyl, 4,4'-dicarboxybenzophenone, bis(4-carboxylphenyl)ethane, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid or their Examples include dicarboxylic acid components such as alkyl ester derivatives. In addition, the glycol components include ethylene glycol,
Propylene glycol, butanediol, neobentyl glycol, diethylene glycol, cyclohexanedimethanol, an ethylene oxide adduct of bisphenol A, and the like can be arbitrarily selected and used. In addition, a small amount of amide bond, urethane bond, ether bond, carbonate bond, etc. may be included as a copolymerization component, in short, 80 mol%
All of the above polyalkylene terephthalates can function as a base resin as long as they have fiber-forming ability and film-forming ability.

Next, titanium compounds and germanium compounds are
It serves as a polycondensation catalyst between an acid component and an alkylene glycol, and any compound can be used as long as it is soluble in the reaction system. For example, titanium compounds include tetraethyl titanate, tetrabutyl titanate, partial hydrolysates of titanium alkoxides, titanic oxalate, titanyl ammonium oxalate, potassium titanyl oxalate, titanium oxyacetylacetonate, titanic fluoride, etc. Germanium compounds include Examples include germanium oxide, germanium acetate, germanium ethoxide, and germanium butoxide.
Each of these polycondensation catalysts may be used alone, or two or more types may be used in an appropriate combination. The amount of these polycondensation catalysts added is not particularly limited, but generally speaking, in the case of titanium compounds, the amount of polycondensation catalyst added is
0.0005-0.1 mol%, more preferably 0.002-0.03
In the case of a germanium compound, it is also in the range of 0.01 to 0.1 mol%, more preferably 0.03 to 0.06 mol%, in terms of germanium atoms. However, if the amount of polycondensation catalyst is too small, the reaction rate will be slow and it will take a long time to obtain a predetermined molecular weight, which is impractical, while if it is too large, the transparency and heat resistance of the resulting polymer will decrease.

Further, the zirconium compound is essential as a particulate forming component for improving slipperiness in the internal particle method described above, and any zirconium compound can be used as long as it is soluble in the reaction system. Typical examples include zirconium alkoxides such as tetra-n-propiozirconate, tetraisopropiozirconate, tetra-n-butylzirconate, and tetra-n-amylzirconate, zirconyl acetate, zirconyl formate, Examples include organic acid zirconyl salts such as zirconyl tartrate, zirconyl oxalate, zirconyl stearate, and zirconyl benzoate; and inorganic acid zirconyl salts such as zirconyl chloride, zirconyl bromide, zirconyl carbonate, and zirconyl ammonium carbonate. The amount of these zirconium compounds added is 80% in terms of zirconium atoms to the polyester produced.
Must be set in the range ~2500ppm,
If it is less than 80 ppm, the amount of fine particles produced is small and the slipperiness of the final product cannot be sufficiently improved. on the other hand
If it exceeds 2,500 ppm, the slipperiness reaches a saturated state, and rather coarse particles are formed, which reduces transparency and worsens the polymer color, which is not preferable. A particularly preferable addition amount is 250 to 1300 ppm. Although the zirconium compound may be added in either solid or liquid form, it is most preferably added as an alkylene glycol solution in order to uniformly disperse the produced particles. If it is added in solid form, it is best to seal it in a polyester vessel and add it to the reaction system. The timing of addition of the zirconium compound should be set from the start of the esterification or transesterification reaction until the polycondensation reaction progresses and the intrinsic viscosity of the reaction product reaches 0.2. Because the viscosity is too high, the fine particles produced become unevenly mixed, making it impossible to obtain a homogeneous product. By the way, the initial polycondensation is almost complete when the intrinsic viscosity of the reactant reaches approximately 0.2, but since the molecular weight of the reaction product at this point is extremely small and the viscosity of the reaction solution is low, up to this point, the zirconium compound can be uniformly dispersed. The zirconium compound may be added simultaneously with the titanium compound and the zirconium compound, which are polycondensation catalysts, or may be added separately.

Note that when carrying out the present invention by transesterification, a transesterification catalyst must be used; however, the exchange catalyst in this case is not subject to particular restrictions, and conventionally known exchange catalysts such as alkali metals, alkali Compounds such as earth metals, zinc, and manganese can be arbitrarily selected and used. Among them, zinc and manganese compounds are recommended as the most preferred transesterification catalysts since they do not impede the transparency of the product. In addition, in the case of the direct weight method (method using free terephthalic acid), amines, ammonium compounds, alkali metal compounds, alkaline earth metal compounds are used as the third component to suppress the production of dialkylene glycol. It is also effective to add basic compounds such as, and all changes in their degree are within the scope of the present technology. Further, the method of the present invention can obtain similar effects when applied to either a batch polymerization method or a continuous polymerization method.

The present invention is roughly configured as described above, but the key point is to select a titanium compound and/or a germanium compound as a polycondensation catalyst, and to specify the amount and timing of addition of a zirconium compound as a fine particle product. As a result, it has become possible to provide a polyester that is excellent in transparency and slipperiness and has fewer product defects such as knobs and fitting eyes.

Next, Examples and Comparative Examples of the present invention will be shown. All parts in the examples mean parts by weight unless otherwise specified.

The esterification reaction rate (ester ratio) was determined from the amount of carboxyl groups remaining in the reaction product and the saponification value of the reaction product. The intrinsic viscosity [η] was measured at 30°C by dissolving the polymer in a mixed solvent of phenol (6 parts by weight) and tetrachloroethane (4 parts by weight). The amount of diethylene glycol in the polymer was determined by decomposing the polymer with methanol and by gas chromatography as mole % relative to ethylene glycol.

The diameter and particle concentration of precipitated particles in the polymer were determined by observing a film formed by the method shown in Examples using a reflective dark field microscope.

The maximum surface roughness (R _T ) and center line average roughness (R _A ) of the film were measured using a Surfcom 300A surface roughness meter, needle diameter: 1 μm, weight: 0.078, measurement reference length: 0.8 mm, cutoff: 0.08. Measured under mm conditions,
Displayed as the average value of 10 points.

Film haze was measured using a direct haze meter (manufactured by Toyo Seiki).

The coefficient of dynamic friction of the film is ASTM-D-1894-
Measurement was conducted in accordance with 63T under the conditions of 23°C, 65% RH, and a tensile speed of 200 m/min.

Example 1 50 parts of terphthalic acid and 28 parts of ethylene glycol were subjected to an esterification reaction using 0.016 parts of germanium dioxide. A slurry consisting of 100 parts of terephthalic acid, 56 parts of ethylene glycol, and 0.032 parts of germanium dioxide was added to the product with an esterification rate of 95%, and the pressure was increased under a nitrogen atmosphere.
The esterification reaction was carried out by setting the reaction temperature to 2.5Kg/cm ² and 240°C, and the esterification rate was determined by reacting for 90 minutes.
95% product was obtained.

Next, the esterification reaction product equivalent to 100 parts of terephthalic acid was transferred to a polycondensation reactor at 240°C, and 0.1
Add 3.8 parts by volume of an ethylene glycol solution of zirconyl acetate at a molar concentration (300 ppm in terms of zirconium based on the produced polyester), stir at the same temperature under normal pressure for 15 minutes, and then heat to 275°C over 30 minutes.
Gradually lower the pressure of the reaction system while increasing the temperature to 0.05
mmHg, and the polycondensation reaction was carried out at the same temperature and pressure for about 80 minutes. [η] of the obtained polyethylene terephthalate was 0.628, and diethylene glycol was 2.4%.
And it was highly transparent.

This polymer was melt-extruded at 290°C, stretched 3.5 times in the longitudinal direction at 90°C and 3.5 times in the transverse direction at 130°C, and then heat-treated at 220°C to obtain a film with a thickness of 15 μm. The coefficient of dynamic friction of this film is 0.5, the film haze is 0.6%, and the maximum surface roughness (R _T ) is 0.21μ
m, and the center line average roughness (R _A ) was 0.028 μm.
When the particles in this film were observed using reflective dark field microscopy, countless particles of 1 to 2 μm were observed, and coarse particles of 5 μm or more were observed at 36 locations under 200x magnification, but none were present. .

Next, using the polymer obtained above, at 285℃
When high-speed spinning was carried out at a discharge rate of g/min and a speed of 6000 m/min, the yarn could be taken off smoothly without any breakage. The obtained yarn had excellent gloss and extremely high transparency.

Comparative Example 1 Example 1 except that zirconyl acetate was not added
The polycondensation reaction was carried out under the same conditions as . The obtained polymer had [η] of 0.625, diethylene glycol content of 2.3%, and was highly transparent.

This polymer was melt-extruded at 290°C, stretched 3.5 times in the longitudinal direction at 90°C and 3.5 times in the transverse direction at 130°C, and then heat-treated at 220°C to obtain a film with a thickness of 15 μm. The slipperiness of the obtained film was extremely poor and a uniform film could not be obtained. Furthermore, the coefficient of dynamic friction of this film was too scaled to be measured, and the film haze was 0.6%.
When the particles in this film were observed using reflective dark field microscopy, no particles were observed at all.

Next, using the polymer obtained above, at 285℃
When high-speed spinning was carried out at a discharge rate of g/min and a speed of 6000 m/min, thread breakage occurred approximately once every 5 minutes, and smooth take-up was not possible.

Comparative Example 2 When polycondensation was carried out under the same conditions as in Example 1 except that germanium dioxide was not added, the [η] of the obtained polymer was as low as 0.412, indicating that satisfactory film formation and fiberization were not achieved. It was possible.

Example 2 519 parts of terephthalic acid, 431 parts of ethylene glycol
and 0.16 parts of triethylamine were charged into a stainless steel autoclave equipped with a stirrer, a distillation column, and a pressure regulator, and after purging with nitrogen, the pressure was increased to a gauge pressure of 2.5.
The esterification reaction was carried out while maintaining the ^temperature at 240°C and continuously removing water produced from the top of the distillation column. 120 minutes after the start of the reaction, the pressure was released,
A product with an esterification rate of 95% was obtained. Potassium titanyl oxalate (dihydrate) is added to this esterification product.
0.020 parts and 1.17 parts of tetra-n-propionizirconate 2n-propyl alcohol salt (in terms of zirconium atoms based on the polyester produced)
400ppm) was added, heated and stirred at 240℃ for 15 minutes at normal pressure, then transferred to a polycondensation reactor at 240℃, and gradually lowered the pressure of the reaction system while raising the temperature to 275℃ over 30 minutes. The pressure was adjusted to 0.05 mmHg, and the polycondensation reaction was further carried out at the same temperature and pressure for about 80 minutes. [η] of the obtained polymer was 0.640, diethylene glycol was 2.1%,
It was highly transparent.

When this polymer was formed into a film in the same manner as in Example 1, a film of almost the same high quality as in Example 1 was obtained. Further, when high-speed spinning was carried out in the same manner as in Example 1, the yarn could be spun smoothly without any breakage, and a yarn with high gloss and transparency was obtained.

Example 3 Add 1000 g of dimethyl terephthalate to the polymerization reaction vessel.
800 parts of ethylene glycol, 0.226 parts of zinc acetate (dihydrate), and heated at 195℃ under nitrogen atmosphere.
Transesterification was performed by heating for 2.5 hours. This transesterification product contains 0.17 germanium dioxide.
part, tetra-n-propiozirconate 2n-
Add 1.95 parts of propyl alcohol salt (401 ppm in terms of zirconium to the polyester produced),
After heating and stirring at the same temperature for 15 minutes, it took 40 minutes to reach 275
Gradually lower the pressure of the reaction system while increasing the temperature to ℃.
The pressure was adjusted to 0.05 mmHg, and polycondensation was further carried out at the same temperature and pressure for about 70 minutes. [η] of the obtained polymer is
0.638, diethylene glycol was 2.5% and highly transparent.

When this polymer is formed into a film in the same manner as in Example 1,
A film of almost the same high quality as Example 1 was obtained. Further, when high-speed spinning was carried out under the same conditions as in Example 1, the yarn could be taken up smoothly without breakage during spinning, and the gloss and transparency of the yarn obtained were extremely good.

Claims (1)

[Claims] 1. In producing polyester from terephthalic acid or its ester-forming derivative and alkylene glycol in the presence of at least one polycondensation catalyst selected from the group consisting of titanium compounds and germanium compounds, polycondensation is carried out from the start of the reaction. A zirconium compound that is soluble in the reaction system is added to the resulting polyester in an amount of 80 to 2,500 ppm in terms of zirconium atoms until the intrinsic viscosity of the reactant reaches 0.2 as the reaction progresses. manufacturing method of polyester.