JP2003113230A - Method for producing polyester and polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester which is produced by using a polycondensation catalyst comprising a metal component except antimony and germanium as the main component of the catalyst, to provide a continuous polycondensation method with which filter and nozzle clogging by foreign matters during molding, transparency, yellowing, heat resistance, etc., are improved and which is stable and to obtain a product thereof. SOLUTION: In this method for producing a polyester by continuous polycondensation by using an oligomer obtained by direct esterification reaction or transesterification reaction between an aromatic or aliphatic dicarboxylic acid or its ester derivative and a diol or its ester derivative, the method for continuous polycondensation of a polyester comprises adding a polyester polycondensation catalyst which is selected from at least aluminum compounds and cobalt compounds and has satisfies conditions of a specific Al/Co molar ratio and Co concentration under conditions of specific oligomer Es (%) (esterification ratio).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polyester, and more specifically, a novel polyester polymerization catalyst which does not use germanium or an antimony compound as a catalyst main component, and continuous polyester polycondensation using the same. It relates to legal and its polyester products.

[0002]

2. Description of the Related Art Polyethylene terephthalate (PE
T), polyesters represented by polybutylene terephthalate (PBT), polyethylene naphthalate (PEN) and the like are excellent in mechanical properties and chemical properties, and depending on the properties of each polyester, for example, for clothing or It is used in a wide range of fields such as fibers for industrial materials, films and sheets for packaging and magnetic tape, bottles that are hollow molded products, casings for electric and electronic parts, and other engineering plastic molded products.

A typical polyester having aromatic dicarboxylic acid and alkylene glycol as main constituents is, for example, polyethylene terephthalate (PE).
In the case of T), bis (2-hydroxyethyl) terephthalate is produced by esterification or transesterification of terephthalic acid or dimethyl terephthalate with ethylene glycol, which is polycondensed with a catalyst at high temperature and under vacuum. It is industrially produced by the polycondensation method or the like. BACKGROUND ART Conventionally, antimony trioxide has been widely used as a polyester polymerization catalyst used during such polycondensation of polyester. Antimony trioxide is a catalyst that is inexpensive and has excellent catalytic activity. However, when it is used as a main component, that is, in an amount added so that a practical polymerization rate is exhibited, metal antimony is produced during polycondensation. Therefore, there is a problem that darkening and foreign matter are generated on the polyester. Under such circumstances, polyesters containing no antimony or no antimony as a catalyst main component are desired. The above-mentioned foreign matter in the polyester causes the following problems, for example.

(1) In the polyester for film, the deposition of metal antimony becomes a foreign substance in the polyester, which not only causes stain on the die during melt extrusion, but also causes surface defects of the film. Further, when used as a raw material for a hollow molded article or the like, it is difficult to obtain a hollow molded article having excellent transparency. (2) The foreign matter in the polyester for the fiber becomes a foreign matter that causes a decrease in strength in the fiber, and becomes a cause of stain on the spinneret during spinning. In the production of polyester fibers, a polyester polymerization catalyst that does not generate foreign matter is required mainly from the viewpoint of workability.

As a method for solving the above problems, attempts have been made to use antimony trioxide as a catalyst and suppress the darkening of PET and the generation of foreign matter. For example, in Japanese Patent No. 2666502, by using a compound of antimony trioxide, bismuth and selenium as a polycondensation catalyst, generation of black foreign matter in PET is suppressed. Further, in JP-A-9-291141,
It is stated that the use of antimony trioxide containing sodium and iron oxides as a polycondensation catalyst suppresses the deposition of metallic antimony. However, these polycondensation catalysts cannot eventually achieve the purpose of reducing the content of antimony in the polyester.

As a method for solving the problems of antimony catalysts in applications requiring transparency such as PET bottles, Japanese Patent Laid-Open No. 6-279579 discloses, for example,
A method is disclosed in which the transparency is improved by defining the amount ratio of the antimony compound and the phosphorus compound used. However, the hollow molded article made of polyester obtained by this method does not have sufficient transparency.

Further, Japanese Patent Application Laid-Open No. 10-36495 discloses a continuous production method of polyester having excellent transparency using antimony trioxide, phosphoric acid and sulfonic acid compounds. However, the polyester obtained by such a method has a problem that the thermal stability is poor and the obtained hollow molded article has a high acetaldehyde content. Polycondensation catalysts that are alternatives to antimony-based catalysts such as antimony trioxide have also been studied, and titanium compounds and tin compounds typified by tetraalkoxy titanates have already been proposed, but polyesters produced using these are There is a problem that the polyester is apt to be thermally deteriorated during the melt molding and the polyester is markedly colored.

As an attempt to overcome the above problems when a titanium compound is used as a polycondensation catalyst, for example, in JP-A-55-116722, tetraalkoxy titanate is used simultaneously with a cobalt salt and a calcium salt. A method has been proposed. In addition, JP-A-8-7
According to Japanese Patent No. 3581, a method is proposed in which a tetraalkoxy titanate is used as a polycondensation catalyst at the same time as a cobalt compound, and a fluorescent whitening agent is used. However,
These techniques reduce the coloring of PET when tetraalkoxy titanate is used as a polycondensation catalyst, but have not achieved effective suppression of thermal decomposition of PET.

As another attempt to suppress thermal deterioration during melt molding of polyester polymerized using a titanium compound as a catalyst, for example, in Japanese Patent Laid-Open No. 10-259296, phosphorous is used after polymerizing a polyester using a titanium compound as a catalyst. A method of adding a system compound is disclosed. However, it is not technically difficult to effectively mix the additive into the polymer after polymerization, and it is not practically used because of cost increase.

Japanese Patent Publication No. 11-507694 discloses that an aluminum compound and a cobalt compound are used in a molar ratio within a specific range. However, in this method, the lack of catalytic activity of the aluminum compound is compensated for by the cobalt compound, so that the obtained polyester has drawbacks such as insufficient heat resistance and reduced brightness. Further, a technique of adding an alkali metal compound to an aluminum compound to obtain a polyester polymerization catalyst having sufficient catalytic activity is also known. When such a known catalyst is used, a polyester having excellent thermal stability can be obtained, but the catalyst in which this alkali metal compound is used in combination requires a large amount of them in order to obtain practical catalytic activity. As a result, at least one of the following problems occurs due to the alkali metal compound in the obtained polyester polymer.

1) The amount of foreign matter becomes large, so that when it is used as a fiber, the threading properties and thread properties are deteriorated, and when it is used as a film, the film properties are deteriorated. 2) The hydrolysis resistance of the polyester polymer decreases, and the transparency decreases due to the generation of foreign matter. 3) Poor color tone of the polyester polymer, that is, a phenomenon in which the polymer is colored yellow, and when used in a film, a hollow bottle, or the like, the color tone of a molded product deteriorates. 4) The filter pressure at the time of melting to produce a molded product increases due to the clogging of foreign matter, and the productivity also decreases.

Germanium compounds have already been put to practical use as catalysts for polyesters having excellent catalytic activity other than antimony compounds and not having the above-mentioned problems, but this catalyst is very expensive. Or
Since it is easy to distill out from the reaction system during the polymerization, there is a problem that the catalyst concentration in the reaction system changes and it becomes difficult to control the polymerization, and there is a problem in using it as a catalyst main component.

Based on the above-mentioned circumstances, it is a polymerization catalyst containing a metal component other than antimony and germanium as a main metal component of the catalyst, and it is a continuous catalyst giving a polyester excellent in catalytic activity and having a small amount of foreign matters and excellent transparency. A polycondensation method is desired. For the continuous polycondensation method of polyester,
For example, the three-can method as disclosed in JP-A-10-316747 and JP-A-10-316747.
-There are 5 to 6 can methods such as 87807 bulletin. However, in the continuous polycondensation method, a large amount of defective products are produced when the brands are switched, so it is important and stable to stabilize the quality at an early stage.

[0014]

DISCLOSURE OF THE INVENTION The present invention provides a novel polyester polycondensation catalyst which does not use germanium or an antimony compound as a catalyst main component, and a method for producing a polyester which can be stably produced by a continuous polycondensation method using the same. It provides the polyester product. Further, the present invention is a polycondensation catalyst containing a main metal component of aluminum, which is excellent in catalytic activity, is excellent in transparency with less generation of foreign matters, and is also excellent in color tone, and the continuous weight of polyester using the polycondensation catalyst. The present invention provides a condensation method and a polyester product thereof. The present invention also uses the catalyst, a film, a hollow molded article such as a bottle,
It is an object of the present invention to provide a polyester polycondensation catalyst which has improved foreign matter generation and productivity during melt molding of fibers, engineering plastics, etc., a polyester continuous polycondensation method using the same, and a polyester product thereof. .

[0015]

DISCLOSURE OF THE INVENTION The inventors of the present invention have obtained bis (2-) obtained from direct esterification reaction and transesterification reaction with aromatic or aliphatic dicarboxylic acid or its ester derivative and diol or its ester derivative.
Hydroxyethyl) terephthalate (BHET) and an oligomer (hereinafter abbreviated as “oligomer”) are used to continuously polycondense a polyester. In the production method, a polycondensation catalyst selected from at least an aluminum compound and a cobalt compound is represented by the following formula ( Provided is a method for producing a polyester to be added to an oligomer satisfying 1). The process provides the process for producing polyesters and polyester products which are the object of the present invention. Es (%) ≧ 60 (1) (where Es (%) in the formula indicates the esterification rate.) Further, the polycondensation catalyst is used as the aluminum (Al) element and cobalt present in the obtained polyester. As the molar ratio of the (Co) element and the amount of the cobalt element, the following formula (2)
It has been found that satisfying the conditions (3) and (3) is more preferable for achieving the object of the present invention. 20 <Al (E) / Co (E) ≦ 100 (2) 1 ≦ Co (E) ≦ 20 (3) (However, Al (E) / Co (E) and Co (E) are the The molar ratio of the remaining aluminum and cobalt elements, and the remaining amount of cobalt element (ppm) are shown.)

Further, an antimony compound may be used in combination so as not to exhibit the inherent defects of the catalyst or to improve the catalytic activity mainly within a reduced specific range. In this case, it is preferable that the amount of antimony element Sb (E) in the remaining polyester satisfies the expression (4). Sb (E) ≦ 100 (4) (However, Sb (E) indicates the amount of antimony element remaining in the polyester (ppm).)

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention specifies the esterification rate of an oligomer obtained from a direct esterification reaction or transesterification reaction with an aromatic or aliphatic dicarboxylic acid or an ester derivative thereof, and a diol or an ester derivative thereof. The present invention relates to a method for continuous polycondensation of polyester, which comprises adding a polycondensation catalyst selected from at least an aluminum compound and a cobalt compound within the range and a polyester product thereof.

As an embodiment of the production method of the present invention, it is necessary to add the polymerization catalyst to a reaction system of an oligomer satisfying Es (%) ≧ 60%. If Es (%) <60%, the carboxylic acid terminal and the catalyst metal react and the amount of foreign matter increases, which is not preferable. More preferably, Es (%) ≧ 80% is added. It is a particularly preferred embodiment to add Es (%) ≧ 90%. However, if it satisfies the above range of Es (%) ≧ 60%, it can be added to the oligomer reaction system at any stage of the polymerization reaction. For example, it can be added to the oligomer reaction system at any stage before or during the esterification reaction or transesterification reaction or immediately before the polycondensation reaction or at any stage during the polycondensation reaction. Further, if the above range of Es (%) ≧ 60% is satisfied, the respective components of the mixed catalyst can be added simultaneously or separately. Further, a mixture of the constituent components of the catalyst may be added in advance, or these may be added separately. In particular, it is preferable to add the aluminum compound immediately before the start of the polycondensation reaction in order to obtain stable quality.

As the aluminum compound constituting the polycondensation catalyst of the present invention, known aluminum compounds can be used without limitation. As the aluminum compound, specifically, aluminum formate, aluminum acetate, basic aluminum acetate, aluminum propionate, aluminum oxalate, aluminum acrylate, aluminum laurate, aluminum stearate, aluminum benzoate, aluminum trichloroacetate, aluminum lactate. Carboxylic acid salts such as aluminum citrate and aluminum salicylate, and inorganic acid salts such as aluminum chloride, aluminum hydroxide, polyaluminum chloride, aluminum carbonate, aluminum phosphate and aluminum phosphonate.

Also, aluminum methoxide, aluminum ethoxide, aluminum n-propoxide,
Aluminum iso-propoxide, aluminum n-butoxide, aluminum t-butoxide and other aluminum alkoxides, aluminum acetylacetonate, aluminum acetylacetate, aluminum ethylacetoacetate, aluminum ethylacetoacetate diiso-propoxide and other aluminum chelate compounds, trimethylaluminum , Organic aluminum compounds such as triethylaluminum, partial hydrolysates thereof, aluminum oxide and the like. Among these, carboxylates, inorganic acid salts and chelate compounds are preferable, and among these, basic aluminum acetate, aluminum chloride, aluminum hydroxide, polyaluminum chloride and aluminum acetylacetonate are particularly preferable.

Examples of the cobalt compound which can be used in the present invention include cobalt acetate tetrahydrate, cobalt hydroxide, cobalt acetonate, cobalt naphthenate and cobalt saltylsalicylate.

The aluminum compound and the cobalt compound, which are polycondensation catalysts added to the oligomer reaction system, are preferably added so as to satisfy the formulas (2) and (3). For that purpose, at the time of polyester polymerization, the formula (2),
It is preferable to add the amounts of the aluminum compound and the cobalt compound represented by (3) as a catalyst. 20 <Al (E) / Co (E) ≦ 100 (2) 1 ≦ Co (E) ≦ 20 (3) (However, Al (E) / Co (E) and Co (E) are the It shows the molar ratio of the remaining aluminum and cobalt elements, and the amount of remaining cobalt element (ppm).) Furthermore, whether the defects inherent in the catalyst used in combination are manifested,
Within certain mitigated ranges, antimony compounds may be used primarily to improve catalytic activity. In this case, the amount of antimony element Sb (E) remaining in the polyester
It is preferable that the expression (4) is satisfied. For that purpose, it is preferable to add an amount of the antimony catalyst represented by the formula (4) at the time of polyester polymerization. Sb (E) ≦ 100 (4) (However, Sb (E) indicates the amount of antimony element remaining in the polyester (ppm).)

The antimony compound may be added at any time from the start to the end of the direct esterification reaction and transesterification reaction.

The antimony compound used in the present invention is not particularly limited. Specific examples of the antimony compound include antimony trioxide, antimony pentoxide, antimony acetate, and antimony glycoside, and of these, antimony trioxide is preferable.

The addition amount of the aluminum compound and the cobalt compound of the present invention is preferably such that the molar ratio of the aluminum element amount and the cobalt element amount to the polymer finally obtained is within the range of the formula (2). The preferable molar ratio of the amount of aluminum element and the amount of cobalt element is 21
˜75, more preferably 25 to 60. When the molar ratio exceeds 100, foreign matter is generated, and when the molar ratio is 20 or less, the color tone and heat resistance are not preferable.

It is known that the cobalt compound of the present invention itself has a certain level of catalytic activity, but as described above, when it is added to such an extent that it exerts sufficient catalytic activity, the polyester compound obtained can be obtained. The brightness (brightness) of the united body and the thermal stability decrease. Therefore, it is preferable to add a small amount mainly for improving the color tone rather than improving the catalytic activity. That is, by keeping the cobalt compound in a small amount as described above and adding an amount such that the catalytic effect is not clear, yellowing is effectively suppressed without causing a decrease in heat resistance and brightness of the resulting polyester. can do.

The amount of elemental cobalt remaining in the polyester of the cobalt compound of the present invention is preferably 1 ppm to 20 ppm, but is preferably 2 to 15 ppm.
More preferably, it is 3 to 10 ppm. If it is less than 1 ppm, the bluing effect is insufficient, which is not preferable. When it exceeds 20 ppm, the brightness (brightness) is lowered and at the same time, the heat resistance of the polymer is gradually lowered, which is an unfavorable mode.

The amount of the antimony element remaining in the polyester of the antimony compound of the present invention is preferably up to 100 ppm, but more preferably 10 ppm to 75 ppm, and still more preferably from the viewpoint of the balance of foreign matter suppression and catalytic activity. Is 30 to 50 ppm.

The polycondensation catalyst of the present invention preferably has a solution form, a slurry form or a neat form. If these are not satisfied, not only the dispersion in the reaction system becomes non-uniform, but also quantitative supply is difficult, which is not preferable.
The solvent is not particularly limited as long as it can dissolve the polycondensation catalyst of the present invention even in a small amount. However, it is preferable to use foreign substances that remain in the polyester, diol components that form the polyester that do not become impurities, or those that distill out of the system during polyester production.

Examples of the solvent include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3- Butylene glycol, 1,4
-Butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol,
1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol,
Aliphatic glycols such as 1,4-cyclohexanediethanol, 1,10-decamethylene glycol, 1,12-dodecanediol, polyethylene glycol, polytrimethylene glycol, polytetramethylene glycol, hydroquinone, 4,4′- Dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy)
Benzene, 1,4-bis (β-hydroxyethoxyphenyl) sulfone, bis (p-hydroxyphenyl) ether, bis (p-hydroxyphenyl) sulfone, bis (p-hydroxyphenyl) methane, 1,2-bis (p
-Hydroxyphenyl) ethane, bisphenol A, bisphenol C, 2,5-naphthalene diol, and aromatic glycols such as glycols obtained by adding ethylene oxide to these glycols.
Further, lower aliphatic alcohols such as methanol, ethanol, isopropanol, propanol, isobutyl alcohol, butanol, pentanol, and hexanol, chloroform, carbon tetrachloride, dichloromethane, perchloroethylene, trichloroethane, trichloroethylene, toluene, benzene, acetone, acetonitrile. ,
Dimethylformamide, ethyl acetate, amyl alcohol, amyl acetate, benzyl alcohol, water, cyclohexanone, dimethylacetamide, dimethylformamide, dioxane, dimethylsulfoxide, ethers such as diethyl ether, formaldehyde, glycerin, hexane, isopropyl acetate,
Methyl ethyl ketone, pentane, phenol, pyridine, xylene, tetrahydrofuran and the like can be mentioned.

The method for preparing the solution is not particularly limited. Physical conditions such as heating, stirring, dissolution time are compounds,
It can be freely selected according to the solvent. For example, liquid-liquid substitution from a readily soluble solvent is also possible. Also the stability of the solution,
Various additives may also be added to improve the solubility.

For example, in the case of an aluminum compound, it is further mixed with water containing an alkali compound, an organic solvent or a mixture of water and an organic solvent in advance, and then added to the reaction system to further suppress the generation of foreign substances in the polyester of the aluminum compound. Therefore, it is preferable. In particular, it is preferable to mix the alkali compound with water to form an aqueous solution, and then mix the aluminum compound with the aqueous solution because the aluminum compound is uniformly dispersed or dissolved in the aqueous solution, and the generation of foreign matter in the polyester is further suppressed. Further, it is preferable to dilute the aqueous solution containing the aluminum compound with a diol component forming a polyester such as ethylene glycol and then add it to the reaction system, because local concentration and the like due to a rapid temperature change are less likely to occur. A compound that volatilizes at a temperature of 280 ° C. or less is preferable because the residual amount in the finally obtained polyester is small and the color tone of the polyester is better.

Specific examples of the alkali compound mentioned here include ammonia, diethylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and hydroxide. Examples thereof include tetrabutylammonium, trimethylbenzylammonium hydroxide, ethylenediamine, tetraethylenediamine, hexamethylenediamine, pyridine, quinoline, pyrroline, pyrrolidone and piperidine.

As other additives, for example, ligand exchange can be performed wholly or partially in order to improve the solubility and dispersion of the polymerization catalyst. In particular, carboxylic acids such as acetic acid and benzoic acid, alcohols, diol components forming polyester, phosphorus compounds such as phosphoric acid, trimethyl phosphate and phenylphosphonic acid, inorganic acids such as hydrochloric acid and sulfuric acid, and the like It is preferable to perform exchange in terms of stability of the solution.

When the concentration of the solution is 0.01 to 20% by weight in terms of metal atoms of the catalyst, the solution stability,
The polyester composition obtained has a good color tone and is preferable.

The polyester referred to in the present invention is a polyester composed of one or more selected from dicarboxylic acids and their ester-forming derivatives and one or more selected from diglycols.

As the dicarboxylic acid, oxalic acid, malonic acid,
Succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 1,3-cyclo Pentanedicarboxylic acid,
Saturated aliphatic dicarboxylic acids exemplified by 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, dimer acid and the like, and ester-forming properties thereof Unsaturated aliphatic dicarboxylic acids exemplified by derivatives, fumaric acid, maleic acid, itaconic acid or the like, or ester-forming derivatives thereof, orthophthalic acid, isophthalic acid, terephthalic acid, 5- (alkali metal) sulfoisophthalic acid, diphenic acid 1,3 naphthalenedicarboxylic acid, 1,4 naphthalenedicarboxylic acid, 1,5 naphthalenedicarboxylic acid, 2,6 naphthalenedicarboxylic acid, 2,7 naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, 4,4'-biphenyl sulfone dicarboxylic acid, 4,4'-biphe Examples thereof include aromatic dicarboxylic acids such as nyl ether dicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p'-dicarboxylic acid, pamoic acid, anthracene dicarboxylic acid, and ester-forming derivatives thereof.

Of these dicarboxylic acids, terephthalic acid and naphthalenedicarboxylic acid, especially 2,6 naphthalenedicarboxylic acid, are preferred from the viewpoint of the physical properties of the resulting polyester, and other dicarboxylic acids are used as constituents, if necessary.

As the glycol, ethylene glycol,
1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,
2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,
Aliphatic glycols such as 4-cyclohexanediethanol, 1,10-decamethylene glycol, 1,12-dodecanediol, polyethylene glycol, polytrimethylene glycol and polytetramethylene glycol, hydroquinone, and 4,4′-dihydroxybisphenol 1,4-bis (β-hydroxyethoxy) benzene, 1,4-bis (β-hydroxyethoxyphenyl) sulfone, bis (p-hydroxyphenyl) ether, bis (p-hydroxyphenyl) sulfone, bis (p-hydroxy) Phenyl) methane, 1,2-bis (p
-Hydroxyphenyl) ethane, bisphenol A, bisphenol C, 2,5-naphthalene diol, and aromatic glycols such as glycols obtained by adding ethylene oxide to these glycols.

Of these glycols, ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol and 1,4-cyclohexanedimethanol are preferred.

The polyester used in the present invention is preferably a polyester whose main acid component is terephthalic acid or its ester-forming derivative or naphthalene dicarboxylic acid or its ester-forming derivative, and whose main glycol component is alkylene glycol.

The polyester whose main acid component is terephthalic acid or its ester-forming derivative or naphthalenedicarboxylic acid or its ester-forming derivative means terephthalic acid or its ester-forming derivative and naphthalenedicarboxylic acid or all the acid components. A polyester containing 70 mol% or more of the ester-forming derivatives in total is preferable, more preferably a polyester containing 80 mol% or more, and further preferably
It is a polyester containing 90 mol% or more.

The polyester whose main glycol component is alkylene glycol is preferably a polyester containing 70 mol% or more of alkylene glycol in total with respect to all glycol components, and more preferably
A polyester containing 80 mol% or more, and more preferably a polyester containing 90 mol% or more. The alkylene glycol referred to herein may have a substituent or an alicyclic structure in the molecular chain.

Examples of the naphthalenedicarboxylic acid or its ester-forming derivative used in the present invention include 1,3 naphthalenedicarboxylic acid, 1,4 naphthalenedicarboxylic acid, 1,5 naphthalenedicarboxylic acid, and 2,6 naphthalenedicarboxylic acid. Acid, 2,7 naphthalene dicarboxylic acid,
Alternatively, ester-forming derivatives thereof are preferable.

As the alkylene glycol used in the present invention, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,
3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4
-Cyclohexanedimethanol, 1,4-Cyclohexanediethanol, 1,10-Decamethylene glycol,
1, 12 dodecanediol and the like can be mentioned. Two or more of these may be used at the same time.

The polyester of the present invention includes polyethylene terephthalate, polytrimethylene terephthalate,
Polytetramethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polycyclohexylene terephthalate, poly (1,4-cyclohexanedimethylene terephthalate), polyethylene naphthalate, polybutylene naphthalate, polypropylene naphthalate polyethylene 2,6-naphthalene dicarboxylate , And copolymers thereof are preferred, and among these, polyethylene terephthalate and copolymers thereof are particularly preferred.

The polyester of the present invention may contain organic, inorganic, and organometallic toners, optical brighteners, and the like. By containing one or more of these, the polyester It is possible to suppress coloring such as yellowishness to an even more excellent level. In addition, any other polymer, antistatic agent, defoaming agent, dyeability improving agent, dye,
Pigments, matting agents, optical brighteners, stabilizers, antioxidants and other additives may be included. As the antioxidant, aromatic amine-based or phenol-based antioxidants can be used, and as the stabilizer, phosphoric acid or phosphate ester-based phosphorus-based, sulfur-based, amine-based, etc. stabilizers can be used. Can be used.

The continuous polycondensation apparatus usable in the present invention includes a slurry tank for preparing raw materials and an esterification reaction tank (1 can, 2 cans or 3 cans) for forming an oligomer by a direct esterification reaction or a transesterification reaction. Each of them can be used, and the final esterification reaction tank is preferably horizontal rather than vertical. In the subsequent polycondensation reaction tank,
Two or three cans may be used, but the final polycondensation reaction tank is preferably horizontal rather than vertical.

[0049]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

(Measurement of Intrinsic Viscosity (IV)) Phenol /
It measured at 30 degreeC using the tetrachloroethane (60:40, weight ratio) mixed solvent.

(Calculation of Oligomer Pn) Pn (degree of polymerization) = [MW + 26-88 × [OHVo / (AVo +
OHVo)]] / (192 + 44E) However, MW (molecular weight (g / mol)) = 10 ⁶ × 2 / (AVo + O
HVo) E = DEG / (EG + DEG) E is the diethylene glycol production mole fraction. DEG is the number of moles of diethylene glycol in the polymer, EG is the number of moles of ethylene glycol.

(Measurement of Oligomer AVo (acid value)) The oligomer is ground and dried under reduced pressure at 110 ° C. for 15 hours or more.
About 1 g of a sample is precisely weighed and 20 ml of pyridine is added. 15
Boil to reflux for minutes to dissolve. After dissolution, 10 ml of pure water is added and the mixture is allowed to cool to room temperature. Titrate with N / 10-NaOH using phenolphthalein as an indicator. Do the same for the blank without sample. When the oligomer does not dissolve in pyridine, it is used in benzyl alcohol. AVo (eq / ton) is calculated according to the following formula. A Vo = (A−B) × 0.1 × f × 1000 / W (A = drop constant (ml), B = blank drop constant (ml), f =
N / 10-NaOH factor, W = sample weight (g))

(Measurement of OHVo (OH Value)) The oligomer is ground and dried under reduced pressure at 110 ° C. for 15 hours or more. About 0.5 g of a sample is precisely weighed and 10 ml of an acetylating agent (0.5 mol% / L of acetic anhydride pyridine solution) is added. After immersing in a water bath at 95 ° C. or higher for 1.5 hours, 10 ml of pure water is added and left to cool to room temperature. N / 5 with phenolphthalein as an indicator
-Titrate with NaOH solution. Do the same for the blank without sample. OHVo (eq / ton) is calculated according to the following formula. OHVo = {(B−A) × 0.2 × f × 1000 / W} +
AVo (A = drop constant (ml), B = blank drop constant (ml), f =
N / 5-NaOH solution factor, W = sample weight (g))

(Measurement of EG and DEG of oligomer)
Collect 0.1 g of the oligomer in a glass ampoule, inject 2 ml of methanol, and then seal the tube with a glass burner. 250
Treat in an autoclave at 100 ℃ / cm ^{2 for} 8 hours.
After cooling, open the ampoule and use a microsyringe to 1 μl.
Are collected and analyzed using gas chromatography.
The mol% of each is calculated using the calibration curves of ethylene glycol (EG) and diethylene glycol (DEG).

(Calculation of esterification rate (Es (%))) Esification rate = {1-AVo / (Pn × (AVo + OHVo))} ×
100

(Measurement of Content of Metal Element) The content of the metal element in the polyester is as follows:
It was determined by high-frequency plasma emission analysis and atomic absorption analysis.

(Color measurement) The color of the chip is shown by L value, a value and b value by a Hunter color difference meter. The larger the L value, the stronger the whiteness, and the larger the b value, the stronger the yellowness.

(Hue change due to heat treatment) After the polymerization, the polymer was discharged into cold water in a strand form to be rapidly cooled, and then held in cold water for 20 seconds, and then cut into a cylinder shape having a length of about 3 mm and a diameter of about 2 mm. I got a resin chip.
The resin chips obtained were heat-treated at 200 ° C. for about 5 hours in an oven, and the hues of the resins with and without heat treatment were visually judged. A: Almost no change in hue is observed. Δ: Little change in hue is observed. X: No noticeable change in hue is observed.

(Increase in filtration pressure during spinning and yarn breakage during drawing) Evaluation of increase in filtration pressure The degree of increase in filtration pressure during spinning was evaluated as follows. ◯: Almost no increase in filtration pressure is observed. Δ: Little increase in filtration pressure is observed. X: No significant increase in filtration pressure is observed. Evaluation of frequency of yarn breakage The frequency of yarn breakage during drawing was evaluated as follows. ◯: Thread breakage hardly occurs. Δ: Some yarn breakage occurs. X: Thread breakage occurs frequently.

(Evaluation of Foreign Substances) The resin was melted and formed into a film, and then the foreign substances were observed with a transmission microscope. The case where almost no foreign matter was recognized was set to 5, and the case where a large amount of foreign matter was very large was set to 1, and the evaluation was made in 5 stages.

Example 1 A polyester continuous polycondensation apparatus consisting of 2 cans of an esterification reaction tank and 3 cans of a polycondensation reaction tank was used and operated at a production amount of about 1 ton / hr. Operating conditions of the esterification reaction tank, the first esterification tank reaction temperature 250 ℃,
100 kPa, 0.5-5 hr, second esterification reaction tank at 255 ℃, 100
It was kPa, 0.5 to 3 hours. In addition, the reaction time in the first and second esterification reactions is adjusted, and ethylene glycol is added as necessary between the second esterification reaction tank and the initial polymerization reaction tank to obtain the desired oligomer. Es
(%) Was obtained. However, antimony trioxide was added in the first esterification reaction tank. A polycondensation catalyst was added to this oligomer so as to obtain the results shown in Table 1 and transferred to the polymerization tank. The polymerization operation condition at this time was 26
0 ~ 270 ℃, 5 ~ 12kPa, residence time about 1 hour, medium-term polymerization reaction tank is 265 ~ 275 ℃, 0.7kPa, residence time about 1 hour,
The final polymerization reactor was 270 to 280 ° C., 0.13 kPa, and the residence time was about 1 hour. The reaction system was purged with nitrogen, and discharged under normal pressure into cold water in a strand form and cut. Various physical properties were measured using the obtained PET resin chip. The results are shown in Table 1.

Example 2 A polyester continuous polycondensation apparatus consisting of an esterification reaction tank, an initial polymerization tank and a final polymerization tank was used, and operation was performed at a production rate of about 1 ton / hr. The operating condition is that the esterification reaction tank, which is the first reaction tank, is 280
C. to 283.degree. C., 80 kPa, residence time 0.5 to 3 hours. First
The reaction time in the esterification reaction in the reaction tank was adjusted, and ethylene glycol was added between the first and second reaction tanks as needed to adjust to a desired oligomer esterification rate. However, antimony trioxide was added in the first esterification reaction tank. Table 1 shows Es (%) of the oligomer transferred to the second reaction tank. A polycondensation catalyst was added to this oligomer so as to obtain the results shown in Table 1 and transferred to the polymerization reaction tank. The polymerization operation conditions at this time were 285 ° C., 3 kPa, and a residence time of 1 at the initial polymerization reaction tank as the second reaction tank.
~ 1.5 hours, the final polymerization reaction tank, which is the third reaction tank, is 283
The temperature was 0.13 kPa and the residence time was about 1 hour. The reaction system was purged with nitrogen and discharged into cold water under normal pressure in a strand form.
I cut it. Various physical properties were measured using the obtained PET resin chip. The results are shown in Table 1.

(Examples 3 to 6) In Example 1, Al
(E) / Co (E) molar ratio, residual amount of Co (E) and oligomer E
A polymer was polymerized in the same manner except that s (%) was changed. The results are shown in Table 1. When antimony trioxide was added, it was added in the first esterification reaction tank.

(Comparative Example 1) The procedure of Example 1 was repeated, except that only Es (%) of the oligomer and antimony trioxide were used as the catalyst, and the remaining amount was changed. The results are shown in Table 1.

(Examples 7 to 9 and Comparative Example 2) In Example 1, any one of the Al (E) / Co (E) molar ratio, the residual amount of Co (E) and the Es (%) of the oligomer was changed. The polymer was polymerized in the same manner except that it was carried out. The results are shown in Table 1. When antimony trioxide was added, it was added in the first esterification reaction tank.

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[Table 1]

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According to the present invention, there is provided a method for continuous polycondensation of polyester using a novel polycondensation catalyst other than antimony compounds. The polyester of the present invention is, for example,
Textiles for clothing, curtains, carpets, textiles for interior and bedding such as futon, textiles for industrial materials such as tire cords and ropes, various woven fabrics, various knitted fabrics, short fiber non-woven fabrics, long fiber non-woven fabrics, etc. Fiber, packaging film, industrial film, optical film, magnetic tape film, photographic film, can laminating film,
Films for contentors, heat-shrink films, gas barrier films, white films, films such as easy-cut films, non-heat-resistant stretched bottles, heat-resistant stretched bottles, direct blow bottles, gas barrier bottles, pressure-resistant bottles, heat-resistant pressure bottles, and other hollow molded articles, A -It can be applied to sheets such as PET and C-PET, various molded products such as glass fiber reinforced polyester, engineering plastics typified by elastomers, and paints and adhesives.

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Claims (10)

[Claims] 1. A process for continuously polycondensing a polyester using an oligomer obtained from a direct esterification reaction or transesterification reaction with an aromatic or aliphatic dicarboxylic acid or its ester derivative, and a diol or its ester derivative. A method for producing a polyester, wherein a polyester polycondensation catalyst selected from at least an aluminum compound and a cobalt compound is added to an oligomer satisfying the following formula (1). Es (%) ≧ 60 (1) (However, Es (%) in the formula indicates the esterification rate.) 2. The aluminum compound is aluminum acetate,
The method for producing a polyester according to claim 1, wherein the polyester is at least one selected from basic aluminum acetate, aluminum chloride, aluminum hydroxide, polyaluminum chloride and aluminum acetylacetonate. 3. The cobalt compound is cobalt acetate tetrahydrate,
The method for producing a polyester according to claim 1 or 2, wherein the polyester is at least one selected from cobalt hydroxide, cobalt acetonate, cobalt naphthenate, and cobalt saltylsalicylate. 4. A continuous polycondensation is a direct esterification reaction or an ester formation reaction to form an oligomer in two cans or three.
The method for producing polyester according to any one of claims 1 to 3, wherein the polyester is produced in a can and the subsequent polycondensation reaction is conducted in two or three cans. 5. A polyester produced by the method for producing a polyester according to any one of claims 1 to 4,
A polyester characterized in that the molar ratio of aluminum (Al) element and cobalt (Co) element and the amount of cobalt element present in the polyester satisfy the following formulas (2) and (3), respectively. 20 <Al (E) / Co (E) ≦ 100 (2) 1 ≦ Co (E) ≦ 20 (3) (However, Al (E) / Co (E) and Co (E) are the The molar ratio of the remaining aluminum and cobalt elements, and the remaining amount of cobalt element (ppm) are shown.) 6. The polyester according to claim 5, wherein the antimony compound is contained in an amount satisfying the formula (4). Sb (E) ≦ 100 (4) (However, Sb (E) indicates the amount of antimony element remaining in the polyester (ppm).) 7. The polyester according to claim 5, wherein the polyester is polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene terephthalate, or polyethylene 2,6 naphthalene dicarboxylate. Listed polyester. 8. A fiber made of the polyester according to claim 5. 9. A film made of the polyester according to claim 5. 10. A bottle comprising the polyester according to claim 5.