JPH01185355A - Polyester composition - Google Patents

Abstract

PURPOSE:To obtain a polyester for fiber or film, improved in its tendency to increase the pressure of filtration by decreasing filter clogging during spinning or film formation, by decreasing the size of an Sb metal particle added to a specified polyester. CONSTITUTION:The title composition comprises a polyester mainly consisting of ethylene terephthalate repeating units, 1-50ppm polygonal Sb metal particles of a major diameter of 0.01-1mu and 10-500ppb of Bi element. Since the Sb metal particles in this composition are fine and uniform, filter plugging during film formation or spinning can be decreased, and the life of filter can be prolonged. When this composition is formed into a film, the number of coarse protrusions on the surface is small and the hue is good. Yarn break can be reduced during spinning and after-processing because the number of coarse particles originating in the Sb metal particles is small, and a fiber product having a good hue and stable quality can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a polyester for fibers or films that has improved filtration pressure increase during spinning or film formation.

[Prior Art] Polyethylene terephthalate or polyester containing ethylene terephthalate as a main repeating unit is extremely valuable industrially for use in fibers and films.

The properties required for such polyesters differ depending on their use, but the common property required for polyesters for film is excellent workability when handling the film, and the property required for polyesters for textiles is excellent workability when handling the film. Fewer breakage and good thread slipperiness. In addition to these required properties, polyester also has an important required property of excellent filterability during spinning or film formation. To improve workability when handling film,
It is necessary to create minute irregularities on the film surface to improve the film properties, but for this purpose, inert inorganic particles are added to polyester, and metal compounds and phosphorus compounds are added during polyester polycondensation reaction. The reactants are precipitated to form internal particles.

However, among the main reactants that produce these internal particles, such as lithium compounds, calcium compounds, and phosphorus compounds, the reduction effect of the phosphorus compounds or the reduction effect of aldehyde groups generated during the polyester polycondensation reaction causes Antimony trioxide, which is used as a condensation reaction catalyst, is reduced during the polycondensation reaction, and antimony metal particles are precipitated into the polymer as particles. These antimony metal particles are precipitated as crystalline particles with a major axis of 1 to 6 μm, and cause fouling of the nozzle during film formation or spinning, and clogging of a filter. Furthermore, the antimony metal particles flowing out of the filter tend to aggregate, causing film tearing and coarse protrusions on the film surface, as well as thread breakage in fibers. In particular, when the major axis of the antimony metal particles is 2 μm or more, filter clogging becomes severe, which significantly shortens the filter cleaning cycle and increases the cost of product films and fibers. Furthermore, when a product film is used for magnetic tape, it has the disadvantage of causing drop irregularities on the product videotape. It is the distance between two parallel lines). In addition, such metal compounds yellow the color of polyester and worsen the color tone of product films and fibers.

For example, Japanese Patent Laid-Open No. 48-4989
No. 1, JP-A No. 49-31793, lead oxide is added before the polycondensation reaction, and JP-A No. 50-1
Various methods have been proposed for preventing the increase in filter filtration pressure, such as by adding a Ni compound during the polycondensation reaction, as in Japanese Patent No. 38092, but the effects thereof are not great.

[Problems to be Solved by the Invention] However, the present inventors have found that such conventional techniques are not very effective in improving the color tone of polyester, suppressing the increase in filter filtration pressure, and reducing film coarse protrusions.

The purpose of the present invention is to reduce the size of antimony metal particles in polyester, thereby reducing the possibility of fouling of the die during film formation.
Reduces filter clogging and suppresses filtration pressure rise,
This invention relates to a polyester composition that can reduce coarse protrusions on the surface of a product filter and reduce yarn breakage during rough spinning.

[Means for Solving the Problems] The object of the present invention described above is to have a long axis of 0.01 μm or more and 1 μm.
polygonal antimony metal particles having a size less than m)
) m or more 50 DI) m or less and bismuth element 1Qp
This can be achieved by using a polyester composition containing ethylene terephthalate as the main repeating unit containing from pb to 50 oppb.

The antimony metal particles of the present invention were evaluated by the following method. That is, 30 g of polyester is dissolved in 379 g of 0-thaloloyenol by stirring for 100'02 hours, and then centrifuged for 60 minutes at 12,000 rpm using a high-speed centrifuge (manufactured by Hitachi T-ki, Ltd.). After washing and vacuum drying this centrifugal sediment, antimony metal particles are quantified by X-ray diffraction.

The size of the antimony metal particles is measured by drying the centrifugal sediment, then photographing and observing the antimony metal particles collected at the bottom of the centrifugal sedimentation tube using a scanning electron microscope.

The polyester of the present invention was centrifugally precipitated by the method described above, and the precipitate was photographed using a scanning electron microscope. It has a polygonal shape, and its major axis is 0.0.
It was a flaky crystal with a size of 1 μm or more and less than 1 μm.

The amount of antimony metal particles in the polyester of the present invention can be evaluated by the above-mentioned centrifugal sedimentation method, and is preferably 1 to 50 ppm, preferably 1 to 20 ppm, and more preferably 1 to 15 ppm, based on the polyester. If the amount of antimony metal particles exceeds 50 pl)m, it is not preferable because the spinneret will become heavily contaminated during film formation and spinning. Regarding the size of the antimony metal particles, the long axis is preferably 0.01 μm or more and less than 1 μm, but preferably 0.01 to 0.5 μm.
m is good. Antimony metal particles exceeding 1 μm are likely to be captured by a filter during membrane formation or spinning, causing an increase in filter filtration pressure. The bismuth element in polyester is obtained by thermally decomposing the sample using a mixture of nitric acid and sulfuric acid, adjusting the volume with dilute hydrochloric acid, reducing it to a hydride using sodium borohydride, and performing atomic absorption spectroscopy using a heated quartz cell. It can be quantified by the method.

The bismuth element in the polyester according to the present invention is 10
I) I)b or more and 500 ppb or less.

Preferably it is 10 to 300 pl)b. If the bismuth element is less than 1 Qppb, the number of precipitated antimony metal particles will decrease, but instead the size of each individual particle will increase, which is undesirable.On the other hand, if it exceeds 500 ppb, the color will be similar to that of polyester or dark and dull. This is undesirable as it reduces the product value.

The polyester of the present invention can be produced by the following method.

In other words, the method for adding bismuth element into polyester is to dissolve or slurry a bismuth compound in a part of ethylene glycol (hereinafter abbreviated as EG), which is a raw material for polyester production, and add it at any stage of the polyester production process. Alternatively, it may be mixed with a catalyst or additives added during the polymerization reaction.

Preferably, the method of adding antimony by mixing it with antimony metal particles added as a polymerization catalyst is effective because it contributes to the reducing action of antimony.

For the addition of bismuth element, conventionally known compounds such as bismuth oxide and bismuth acetate may be used, and an antimony compound used as a catalyst, particularly bismuth element contained in antimony oxide, may be used. .

The polyester in the present invention has ethylene terephthalate as its main repeating unit, and can be obtained by polycondensation after a transesterification reaction using a generally known lower alkyl terephthalic acid ester such as dimethyl terephthalate and EG as raw materials, or by polycondensation with terephthalic acid ( TP below
Abbreviated as A. ) and EG as raw materials by esterification and then polycondensation. Of course, it may be manufactured by either of these methods, and may be either a batch method or a continuous method. Additionally, dibasic acids such as isophthalic acid, phthalic acid, and diethylene glycol, and polyhydric alcohols may be added or copolymerized. Inert inorganic particles such as calcium carbonate and silica may be added during the manufacturing process, or additive compounds may be mixed together. It may contain particles precipitated by reactions during the process, so-called internal particles, and there are no restrictions on the catalysts, additives, and modifiers to be added as long as they do not depart from the gist of the present invention.

[Example 1] The present invention will be explained in more detail below with reference to Examples. Note that parts in the examples represent parts by weight.

In addition, the bismuth element content in antimony trioxide in the examples is determined by atomic absorption spectroscopy, and the intrinsic viscosity is ○.
-Values at 25°C using talolophenol as a solvent.

-〇 Example 1 85.8 parts of terephthalic acid and 38.5 parts of ethylene glycol
0.023 parts of antimony trioxide containing 450 ppm of bismuth element and 0.08 parts of trimethyl phosphate were added to the low polymer of bis-β-hydroxylethyl terephthalate obtained by esterification reaction of 1.0 parts at 260°C for 4 hours.
1 part, and 0.15 parts of calcium acetate were added thereto, and a polycondensation reaction was carried out at 290'C under reduced pressure of 0.5 mHCl for 3 hours.

The obtained polymer had a good color tone and an intrinsic viscosity of 0.618. The average major diameter of the precipitated antimony metal particles was 0.3 μm based on the results of the scanning electron micrograph obtained by the above-mentioned evaluation method, and there were no particles larger than 1 μm. Further, the amount of antimony metal particles relative to the polymer was 11 ppm, and the amount of bismuth element in the polyester was 98 ppb.

The film obtained by forming this polymer had very good film forming properties, with few rough protrusions on the surface, and little dirt on the die and clogging of the filter during film forming.

Example 2 Same as Example 1 except that in Example 1, the amount of trimethysiflu sulfate added was 0.20 parts, the amount of calcium acetate added was 0.08 parts, and the pressure reduction rate at the initial stage of the polycondensation reaction was accelerated. It was carried out using the following method. The antimony metal particles in the obtained polyester film had a long diameter of 0.9 μm, the content was 1"IpI)m, and the bismuth content in the polymer was 95 ppb. Both the polymer properties and the film properties were good. Met.

Example 3 0.08 part of calcium acetate and 0.020 parts of the same antimony trioxide as in Example 1 were added to 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol, and a transesterification reaction was carried out in the usual manner, followed by phosphorous acid. 0.018 part was added and the excess ethylene glycol was distilled off, resulting in a polycondensation reaction of bis-β-bitroxylethyl terephthalate for 2 hours and 40 minutes under reduced pressure of 0.5 ml-IQ or less as usual. .

-11 = The obtained polyester has a good color tone and an intrinsic viscosity of 0.620.
The antimony metal particles have a long diameter of 0.01 μm and contain 1 ppm of antimony metal particles, and the bismuth element contains 1 oo
It contained ppb.

Furthermore, the film obtained from this polymer had good film formability and quality.

Example 4 The same antimony trioxide as in Example 1 was used, the amount added was 0.005 parts, and the amount of calcium acetate added was 0.005 parts.
05 parts, 1 to 0.0 of added amount of remethyl phosphate
At the same time, bismuth trioxide is made into a slurry of ethylene glycol, and bismuth trioxide is 0.0
It was carried out in the same manner as in Example 1 except that 0,001 parts were added.

The obtained polyester had a good color tone, the long diameter of the antimony metal particles contained therein was 0.3 μm, and the content was 1 ppm. Moreover, the content of bismuth element was 97 ppb. The film obtained by forming this polymer had good surface properties and film formability.

Example 5 In Example 1, antimony trioxide containing 190 ppm of bismuth element was used, and the amount added was 0.10 ppm.
It was carried out in the same manner as in Example 1, except that The obtained polyester had a good color tone, and the film obtained from this polymer also had good film formability and quality.

Example 6.7 The same method as in Example 1 was carried out except that antimony trioxide containing bismuth element as shown in Table 1 was used in Example 1.

The color tone of the obtained polyester and the properties of the film obtained by forming this polymer into a film were both good.

Comparative Example 1 The same method as in Example 1 was carried out except that antimony trioxide containing bismuth element was used.

The antimony metal particles in the obtained polyester have a major diameter of 2
．． It was 5 μm and the content was 12 ppm.

Furthermore, no bismuth element was detected in the polymer. The color tone of this polymer was yellowish, and the number of rough protrusions on the surface of films made from this polymer increased, and the filtration pressure during film formation also increased sharply.

Comparative Example 2 A test was carried out in the same manner as in Example 1, except that antimony trioxide having a bismuth element content of 3000 pI)m was used in Example 1. The bismuth content in the polymer was as high as 650 ppb, and the color tone of the polymer became dark and dull.

Comparative Example 3 In Example 1, the same antimony trioxide was used, the amount added was 0.06 parts, and the amount of trimethyl phosphate was 0.2 parts.
It was carried out in the same manner as in Example 1 except that the amount was 5 parts. Compared to Examples, the content of antimony metal particles in the Bevolima was as high as 65 ppm, and the color tone of the polymer was yellowish.

[Effects of the Invention] In the polyester composition of the present invention, the antimony metal particles are fine and uniform, so that there is less clogging of the filter during film formation or spinning, and the life of the filter can be extended. Furthermore, when made into a film product, there are fewer rough protrusions on the surface and the color tone is also good. On the other hand, in the spinning and post-processing processes, there are fewer coarse particles caused by antimony metal, so there is less yarn breakage and the color tone is good.
Textile products with stable quality can be obtained.

Claims (1)

[Claims] A polyester composition whose main repeating unit is ethylene terephthalate, which contains polygonal antimony metal particles having a major axis of 0.01 μm or more and less than 1 μm in an amount of 1 ppm or more and 50 ppm or less and a bismuth element of 10 ppb or more and 500 ppb or less.