JP2003238673A - Method for producing polyester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polyester having good color and excellent moldability without containing an antimony compound substantially. <P>SOLUTION: This method for producing a polyester comprises polycondensation of a product that is obtained by an esterification reaction or an ester interchange reaction between an aromatic dicarboxylic acid or its ester formable derivative and a diol or its ester formable derivative, wherein the method comprises usage of a titanium complex as a polycondensation catalyst and addition of a dye as a color adjusting agent. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing polyester.

[0002]

2. Description of the Related Art Due to its excellent properties, polyester is widely used in various fields including fibers, films and bottles. Among them, polyethylene terephthalate is preferably used because of its excellent mechanical strength, chemical properties, dimensional stability and the like.

Polyethylene terephthalate is generally produced from terephthalic acid or its ester-forming derivative and ethylene glycol. In commercial processes for producing high molecular weight polymers, antimony compounds are widely used as polycondensation catalysts. . However, polymers containing antimony compounds have some unfavorable properties as described below.

For example, it is known that when a polyester obtained by using an antimony catalyst is melt-spun to form a fiber, the residue of the antimony catalyst is deposited around the spinneret holes. If this deposition progresses, it will cause defects in the filament, and therefore it will be necessary to remove it in a timely manner. It is considered that the deposition of antimony catalyst residue occurs because the antimony compound in the polymer is denatured in the vicinity of the mouthpiece, a part of which vaporizes and dissipates, and then the antimony-based component remains in the mouthpiece. .

Further, the antimony catalyst residue in the polymer is liable to form relatively large particles and becomes foreign matter, which causes increase in filter pressure of the filter during molding, yarn breakage during spinning or film tearing during film formation. It has undesirable characteristics such as

From the above background, there is a demand for polyesters having a low or no antimony content.

From such a background, when compounds other than antimony compounds are required to function as polycondensation catalysts, titanium compounds and germanium compounds are known, but germanium compounds are very expensive and should be used for general purposes. Is difficult On the other hand, the use of a titanium compound, which is relatively inexpensive and highly active, has also been investigated, but this compound has a problem that the color tone and heat resistance of the polymer are lowered.

On the other hand, the color tone of the titanium-based catalyst,
As a method for improving the problem of heat resistance, for example, WO95 / 1
No. 8839 proposes a method using a complex oxide of titanium and silicon as a catalyst, and JP 2001-895557 proposes a titanium compound catalyst obtained by hydrolyzing a titanium halogen compound. When polyester is used for fiber applications, problems such as frequent yarn breakage due to catalyst-induced foreign substances and increased filtration pressure during polymer filtration cannot be solved sufficiently, or there is a slight difference in color tone. However, there is a problem that the color tone is not sufficiently improved for use in clothing.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a polyester which does not substantially contain an antimony compound, has a good color tone and is excellent in moldability.

[0010]

The above-mentioned object of the present invention is a product obtained by an esterification reaction or transesterification reaction with an aromatic dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative. In the method for producing a polyester by polycondensation of a polyester, a titanium complex is used as a polycondensation catalyst, and a color tone adjusting agent is further added to achieve a polyester production method.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester of the present invention is a polymer synthesized from a dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative, and can be used as a molded article such as a fiber, a film or a bottle. There is no particular limitation as long as it is possible.

Specific examples of such polyesters include polyethylene terephthalate, polypropylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate,
Polyethylene-2,6-naphthalene dicarboxylate
And polyethylene-1,2-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate. The present invention is suitable for the most commonly used polyethylene terephthalate or a polyester copolymer mainly composed of polyethylene terephthalate.

In addition to diethylene glycol, these polyesters include, as copolymerization components, dicarboxylic acids such as adipic acid, isophthalic acid, sebacic acid, phthalic acid, 4,4'-diphenyldicarboxylic acid and ester-forming derivatives thereof, polyethylene. Dioxy compounds such as glycol, hexamethylene glycol, neopentyl glycol, and polypropylene glycol, oxycarboxylic acids such as p- (β-oxyethoxy) benzoic acid, and ester-forming derivatives thereof may be copolymerized.

The titanium complex used as a polycondensation catalyst in the present invention is a titanium compound containing a chelating agent capable of coordinating to a titanium atom, and is not particularly limited, but among them, a titanium complex of polyvalent carboxylic acid. The use of a compound is preferable because the color tone of the obtained polymer is good and the generation of foreign matter is small. Particularly, a titanium complex of hydroxy polycarboxylic acid or nitrogen-containing polycarboxylic acid is preferable. As a chelating agent for forming such a titanium complex, phthalic acid, trimellitic acid, trimesic acid, hemimellitic acid, polyvalent carboxylic acid such as pyromellitic acid, malic acid, hydroxy polyvalent carboxylic acid such as citric acid, Nitrogen-containing polyvalent carboxylic acids such as ethylenediamine tetraacetic acid, hydroxyethylimino diacetic acid, diethylenetriamine pentaacetic acid and triethylenetetramine hexaacetic acid can be mentioned.

The titanium compound used as the polycondensation catalyst in the present invention is preferably added to the resulting polyester in an amount of 0.5 to 150 ppm in terms of Ti atom because the polymerization activity is high and the color tone and heat resistance of the resulting polymer are good. The amount is more preferably 1 to 100 ppm, still more preferably 3 to 50 ppm.

The titanium complex used as the polycondensation catalyst in the present invention has a catalytic activity not only for the polycondensation reaction but also for the esterification reaction and the transesterification reaction. A polycondensation reaction may be subsequently performed. At this time, if necessary, a titanium complex may be additionally added before the start of the polycondensation reaction.

The color tone adjusting agent of the present invention is a dye used in resins and the like, and is COLORINDEX GENE.
To give a specific example of RIC NAME, SOLVENT
BLUE 104, SOLVENT BLUE 12
2, SOLVENT BLUE 45 and other blue color tone adjusting agents, SOLVENT RED 111, SOLVEN
T RED 179, SOLVENT RED 19
5, SOLVENTRED 135, PIGMENT
RED 263, VAT RED 41 and other red color tone adjusting agents, DESPERSE VIOLET 26, SO
LVENTIOLET 13, SOLVENT VI
Examples of the purple color tone adjusting agent include OLET 37 and SOLVENTIOLET 49. Among these, SOLVENT BLU, which does not contain halogen, which tends to cause equipment corrosion, has relatively good heat resistance at high temperatures and excellent color development.
E 104, SOLVENT BLUE 45, SOL
VENT RED 179, SOLVENT RED
195, SOLVENT RED 135, SOLVE
NT VIOLET 49 is preferably used.

Further, one or more kinds of these color tone adjusting agents can be used depending on the purpose. In particular, it is preferable to use one or more types of blue-type adjusting agent and red-type adjusting agent, because the color tone can be finely controlled. Further, in this case, it is preferable that the ratio of the blue-based adjusting agent to the total amount of the color-adjusting agent added is in the range of 65 to 95 wt% because the obtained polyester has a particularly good color tone.

Finally, the total amount of the color tone adjusting agent added to the polyester is preferably 30 ppm or less. If it exceeds 30 ppm, the transparency of the polyester may be deteriorated or a dull color may be formed.

The color adjusting agent is preferably added to the polyester at any time after the completion of the esterification reaction or transesterification reaction and the completion of the polycondensation reaction. In particular, it is preferable to add it after the completion of the esterification reaction or the transesterification reaction and before the start of the polycondensation reaction because the dispersion in the polyester is good.

It is also possible to add the color tone adjusting agent to the polyester after the polycondensation reaction is substantially completed. In this case, a method of directly melt-kneading the color tone adjusting agent into the chips using a single-screw or twin-screw extruder, or separately preparing a polyester containing the color tone adjusting agent in a high concentration in advance to prepare the color tone adjusting agent It may be blended with chips that do not contain it.

In the polyester of the present invention, it is preferable to add a lithium compound to the polyester in an amount of 0.1 to 30 ppm in terms of lithium atom at any time before the completion of the polycondensation reaction because the polymer has a good color tone. More preferably, it is 0.5-10 ppm. Such a lithium compound is not particularly limited, but examples thereof include lithium carbonate and lithium acetate.

In the polyester of the present invention, when a cobalt compound is added at an arbitrary time until the completion of the polycondensation reaction so that the amount of the cobalt compound is 1 to 50 ppm in terms of cobalt atom, the color tone becomes good, and the polycondensation is also conducted. It is preferable because the reactivity is increased and a polymer having a high degree of polymerization is likely to be formed. More preferably, it is 3-40 ppm. The cobalt compound is not particularly limited, but specific examples thereof include cobalt chloride, cobalt nitrate, cobalt carbonate, cobalt acetylacetonate, cobalt naphthenate, and cobalt acetate tetrahydrate. In the present invention, it is preferable to use a cobalt compound and a lithium compound at the same time because the polymer color tone is particularly good.

Further, in the present invention, it is preferable that the color tone adjusting agent and the cobalt compound are used in combination and the addition amount of both satisfies the formula (1) because the heat resistance and the color tone are improved. That is, although the cobalt compound has an excellent effect of improving the color tone, it is a factor that reduces the heat resistance of the polymer.
Although the color tone modifier has little effect on the heat resistance of the polymer, it easily lowers the L value. Therefore, by using both in combination, it is possible to avoid adding a large amount of either one, and both heat resistance and color tone are better. Becomes

0.05 ≦ CL / CO ≦ 5 Formula (1) [wherein CL is the amount of the color tone adjusting agent added to the polyester (ppm), and CO is the addition of the cobalt compound in terms of cobalt atoms to the polyester. The amount (ppm) is shown. ] More preferably, it is Formula (2).

0.1 ≦ CL / CO ≦ 3 Formula (2) In the present invention, the polycondensation reaction is optional until the color tone of the polymer is improved or the heat resistance of the obtained polymer is improved. Although a phosphorus compound may be added at the time of, since the titanium compound as a polycondensation catalyst is easily deactivated, the obtained polymer has a phosphorus atom conversion of 15
It is preferable to add it so as to be less than ppm. It is more preferably 10 ppm or less. Further, it is preferable to stagger the addition timing of the phosphorus compound and the polycondensation catalyst because the delay of the polycondensation time is reduced. Here, the phosphorus compound is not particularly limited, and examples thereof include phosphoric acid, phosphorous acid, phosphonic acid, phosphinic acid, and esters thereof.

In the present invention, in order to improve the process passability when molding the obtained polyester into a fiber or film, or to improve the color tone, inorganic particles or inorganic particles are added at any time until the polycondensation reaction is completed. It is preferable to add the polymer particles in an amount of 0.01 to 10 wt% with respect to the polyester. Of these, titanium oxide particles that are inexpensive and have excellent dispersibility in a polymer are preferably used.

Here, the content of titanium oxide particles is 0.05.
It is preferable that the content is ˜7 wt% because the process passability during molding is particularly good, and more preferably 0.1 to 3 wt%.
%. The average particle size is preferably 0.1 to 3 μm. The titanium oxide particles referred to here are
Particles that are generally used for improving the processability in the yarn making process or the film forming process and adjusting the color tone of the product, and do not substantially have the function of the polyester polymerization catalyst. Is.

Since the polyester of the present invention has an excellent color tone, it can be preferably used particularly for fiber applications, especially for clothing applications. At this time, as the color tone of the polyester, in particular, the Hunter value has an L value of 60 or more and an a value of -4 to
When the 0 and b values are in the range of -0.5 to 5, the color tone of the textile product is good, which is preferable. Particularly preferably, the L value is 65 or more, the a value is -2 to 0, and the b value is 0 to 3.

In the polyester composition of the present invention, it is preferable that the content of the antimony compound and the content of the germanium compound are small, and each is 20 pp in terms of metal atom.
When it is m or less, the occurrence of stains on the die during molding is significantly reduced, and a relatively inexpensive polymer can be obtained. More preferably, the content of each compound is 10 ppm or less, and particularly preferably substantially no.

The production method of the present invention will be described using polyethylene terephthalate as an example. The high molecular weight polyethylene terephthalate used for fibers, films and the like is usually produced by any of the following processes. That is, (1) a process in which terephthalic acid and ethylene glycol are used as raw materials, a low molecular weight polyethylene terephthalate or oligomer is obtained by a direct esterification reaction, and then a high molecular weight polymer is obtained by a polycondensation reaction, (2) dimethyl terephthalate and ethylene This is a process in which a low molecular weight substance is obtained by a transesterification reaction using glycol as a raw material, and then a high molecular weight polymer is obtained by a polycondensation reaction thereafter. Here, the esterification proceeds even without a catalyst, but in the transesterification reaction, it is usually allowed to proceed using a compound such as manganese, calcium, magnesium, zinc, lithium or titanium as a catalyst, and the transesterification reaction is substantially carried out. After the reaction is completed, a phosphorus compound may be added for the purpose of inactivating the catalyst used in the reaction.

The production method of the present invention comprises (1) or (2)
Of the low polymer obtained in any stage of the series of reactions, preferably in the first half of the series of reactions (1) or (2), with a titanium compound as a color adjusting agent and a polycondensation catalyst, and if necessary, Titanium oxide, a lithium compound, a phosphorus compound, a cobalt compound or the like is added as particles and polycondensation is performed to obtain a high molecular weight polyethylene glycol. Further, as described above, the color tone adjusting agent may be kneaded in after the completion of the polyester polymerization reaction.

The above reaction is carried out in a batch system, a semi-batch system, a continuous system or the like, but the production method of the present invention can be applied to any of these systems.

[0034]

The present invention will be described in more detail with reference to the following examples. The physical property values in the examples were measured by the methods described below. (1) Intrinsic viscosity of polymer [η] It was measured at 25 ° C using orthochlorophenol as a solvent. (2) Color tone of polymer Hunter value (L, a, b) was measured using a color difference meter (SM color computer model SM-3) manufactured by Suga Test Instruments Co., Ltd.
Value). (3) Content of Titanium, Cobalt, Phosphorus, and Lithium in Polyester It was determined by fluorescent X-ray or ICP (inductively coupled plasma) emission analysis. If necessary, the following pretreatment is performed to remove the influence of inorganic particles such as titanium dioxide particles in the target polyester, followed by fluorescent X-ray or ICP.
Emission analysis was performed. That is, polyester is dissolved in orthochlorophenol, and the viscosity of the polymer solution is adjusted with chloroform as necessary, and then the particles are settled by a centrifuge. Then, only the supernatant liquid is collected by the gradient method, and the polymer is reprecipitated by adding acetone, filtered, and washed to obtain a polymer from which particles have been removed. Metal analysis was performed on the polymer obtained by removing the particles obtained by the above pretreatment. (4) Carboxyl end group amount of polyester (COO
H) Method of Maurice et al. [Anal. Chim. Act
a, 22, p363 (1960)].

Example 1 A catalyst-free oligomer prepared by a conventional method from high-purity terephthalic acid and ethylene glycol was melted at 250 ° C. and stirred to obtain titanium oxide particles in the melt in an amount of 0.3 with respect to polyester. It was added so that it would be wt%. After stirring for 5 minutes, the color adjuster SOLVENT B
7 pp for polyester to obtain LUE 104
m, and after further stirring for 5 minutes, the titanium malate chelate is added to the polyester to be 15 ppm in terms of titanium atom, and then the low polymer is reacted with stirring at 30 rpm. System is 250 ℃
Temperature is gradually raised from 40 to 290 ° C and the pressure is increased to 40
Lowered to Pa. The time required to reach the final temperature and the final pressure was both 60 minutes. When the predetermined stirring torque is reached, the reaction system is purged with nitrogen and returned to normal pressure to stop the polycondensation reaction,
The mixture was discharged into cold water in a strand form and immediately cut to obtain polyester pellets. The time from the start of depressurization until the predetermined stirring torque was reached was 3 hours.

The polymer obtained has an intrinsic viscosity of 0.63,
The color tone of the polymer is L = 74, a = -4.5, b = 0.5.
Met. Moreover, it was confirmed that the content of titanium atoms derived from the titanium catalyst measured from the polymer was 15 ppm.

After the pellets were dried, they were fed to an extruder type spinning machine and melt-spun at a spinning temperature of 295 ° C. At this time, a metal non-woven fabric having an absolute filtration accuracy of 10 μm was used as a filter, and a round hole having a diameter of 0.6 mm was used as a die. Thread discharged from the mouthpiece is 30 cm in length and 25 cm in inner diameter
After gradually cooling with a heating cylinder of φ and temperature of 300 ℃, apply chimney cooling air to cool and solidify the oil, and refuel, then take-off speed 550m
/ Min. This unstretched yarn was stretched at a stretching temperature of 95 ° C. while appropriately changing the stretch ratio so that the stretched yarn has an elongation of 14 to 15%, and then heat treated at a heat treatment temperature of 220 ° C. and a relaxation rate of 2.0%. I got a thread.

In the melt spinning process, there was little increase in filtration pressure during spinning, and there was almost no yarn breakage during drawing, and the polymer had good moldability.

Examples 2 and 3 Polymers were polymerized and melt-spun in the same manner as in Example 1 except that the addition amount of the polycondensation catalyst and the kind and amount of the color adjusting agent were changed as shown in Table 1. It was The polymerization time was 3 hours, and the amount of titanium oxide particles added was 0.3 wt%.

Example 4 After adding titanium oxide particles to the reaction system in Example 1, cobalt acetate and dimethylphenylphosphonate were added,
After stirring for 5 minutes, the polymer was polymerized and melt-spun in the same manner except that titanium nitrilotriacetic acid was added as a polycondensation catalyst.

Examples 5 to 9 and Comparative Examples 1 to 4 The addition amount of the polycondensation catalyst, the addition of the phosphorus compound or the cobalt compound as the concomitant compound, and the kind and amount of the color tone adjusting agent were changed as shown in Table 1 or 2. The polymer was polymerized and melt-spun in the same manner as in Example 4 except for the above. Polymerization time is 3 hours, addition amount of titanium oxide particles is 0.3 wt%
Unified.

In Comparative Example 1, the yarn-forming property was unstable and the yarn breakage was remarkable. In Comparative Examples 2 and 3, the filtration pressure during spinning was significantly increased. In Comparative Example 4, the polymer had a high b value in terms of color tone.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

EFFECT OF THE INVENTION The polyester of the present invention has an excellent color tone, and solves the problems of yarn breakage, film breakage, stain on the base and the like in the production of molded articles for fibers, films, bottles and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J029 AA03 AB05 AD01 AE01 AE02                       AE03 BA02 BA03 BA05 BA08                       CB06A CC06A CG22X JB161                       JC121 JF023 JF321 JF323                       JF453 JF573 KB04 KB05                       KB17

Claims (13)

[Claims] 1. A method for producing a polyester by polycondensing a product obtained by an esterification reaction or an ester exchange reaction with an aromatic dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative, A method for producing polyester, which comprises using a titanium complex as a polycondensation catalyst and further adding a color tone adjusting agent. 2. The method for producing a polyester according to claim 1, wherein the polycondensation catalyst is a titanium complex compound having a polycarboxylic acid as a chelating agent. 3. The method for producing a polyester according to claim 1, wherein the polycondensation catalyst is a titanium complex compound using a hydroxypolycarboxylic acid or a nitrogen-containing polycarboxylic acid as a chelating agent. 4. The method for producing a polyester according to claim 1, wherein the color tone adjusting agent is added after the esterification reaction or the transesterification reaction is substantially completed. 5. The method for producing a polyester according to claim 1, wherein the color tone adjusting agent is added after the polycondensation reaction is substantially completed. 6. The production of the polyester according to claim 1, wherein the lithium compound is added in an amount of 0.1 to 30 ppm with respect to the polyester obtained in terms of lithium atom at any time until the completion of the polycondensation reaction. Method. 7. The method for producing a polyester according to claim 1, wherein the cobalt compound is added in an amount of 1 to 50 ppm with respect to the polyester obtained in terms of cobalt atom at any time until the completion of the polycondensation reaction. 8. The method for producing a polyester according to claim 7, wherein the addition amounts of the color tone adjusting agent and the cobalt compound satisfy the formula (1). 0.05 ≦ CL / CO ≦ 5 Formula (1) [where CL is the amount of the color tone adjusting agent added to the polyester (ppm), and CO is the amount of the cobalt compound converted to the polyester in terms of cobalt atoms (ppm) ) Is shown. ] 9. The method for producing a polyester according to claim 1, wherein at least one type of blue-type adjusting agent and at least one type of red-type adjusting agent are added as color tone adjusting agents. 10. The method for producing a polyester according to claim 9, wherein the ratio of the blue-based adjusting agent to the total amount of the color adjusting agent added is 65 wt% or more and 95 wt% or less. 11. The method according to any one of claims 1 to 10, wherein the phosphorus compound is added so as to be less than 15 ppm in terms of phosphorus atom with respect to the polyester from which a phosphorus compound can be obtained at any time until the completion of the polycondensation reaction. 2. The method for producing a polyester according to item 1. 12. A polyester capable of obtaining titanium oxide particles at an arbitrary time until the completion of the polycondensation reaction is 0.
The method for producing a polyester according to any one of claims 1 to 11, wherein the addition is performed so as to be from 01 to 10 wt%. 13. The color tone of the obtained polyester has a Hunter value, an L value of 60 or more, an a value of −4 to 0, and a b value of −0.5 to 5, respectively. 1
13. The method for producing a polyester for fibers according to any one of 1 to 12.