JP2001278971A - Polyester production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of polyester which has an excellent color tone, few foreign matters in its polymer, and has an outstanding melt heat stability. SOLUTION: When a trimethylene glycol ester of an bifunctional aromatic carboxylic acid and/or its low polymerizate or tetramethylene glycol ester of the carboxylic acid and/or its low polymerizate is subjected to a polycondensation reaction in the presence of a catalyst to produce a polyester, a reaction product obtained from previous reaction between a specific titanium compound and a phosphorus compound is used as this catalyst at the molar rate of (1/1)-(3/1).

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 a polyester, and more particularly, to a method for producing a polyester having a good color tone, a small amount of foreign matters, and an excellent melt heat stability.

[0002]

2. Description of the Related Art Polyesters, particularly polytrimethylene terephthalate and polybutylene terephthalate, are widely used for fibers, films and other molded products because of their excellent mechanical, physical and chemical properties.

For example, polytrimethylene terephthalate is usually subjected to a direct esterification reaction between terephthalic acid and trimethylene glycol, a transesterification reaction between a lower alkyl ester of terephthalic acid such as dimethyl terephthalate and trimethylene glycol, or Reacting terephthalic acid with trimethylene oxide to form a glycol ester of terephthalic acid and / or a low polymer thereof, and then heating the reaction product under reduced pressure in the presence of a polymerization catalyst to obtain a predetermined degree of polymerization. It is produced by a polycondensation reaction.

It is well known that the type of the catalyst used in the polycondensation reaction step greatly affects the reaction rate and the quality of the obtained polyester, and the polycondensation catalyst for polytrimethylene terephthalate is an antimony compound. Is most widely used because it has excellent polycondensation catalyst performance and a polyester having a good color tone can be obtained.

[0005] However, when the antimony compound is used as a polycondensation catalyst, the obtained polyester is melt-spun continuously over time, and foreign substances (hereinafter, sometimes simply referred to as die foreign substances) adhere around the die hole. Bending phenomenon of bending and accumulating molten polymer flow (bending)
This causes a problem of moldability such as generation of fluff or breakage in the spinning and drawing steps.

[0006] Also, with the recent increase in environmental consciousness, it is not desirable to use a highly toxic metal such as antimony as a catalyst even if it is in a very small amount. In particular, polyesters containing no antimony have been demanded. I have.

As a polycondensation catalyst other than the antimony compound, it has been proposed to use a titanium compound such as titanium tetrabutoxide. However, when the titanium compound is used, the polyester obtained is as described above. Although the problem of moldability caused by the accumulation of foreign matter can be solved, a new problem occurs in that the polyester itself is colored yellow, and the melt heat stability is poor.

[0008] In order to solve the coloring problem, it is common practice to add a cobalt compound to polyester to suppress yellowing. Certainly, the hue of the polyester can be improved by adding the cobalt compound, but there is a problem that the addition of the cobalt compound lowers the melting heat stability of the polyester, and the polymer is easily decomposed. Further, the cobalt compound has high toxicity, and it is preferable not to use it from the viewpoint of the above-mentioned environment.

As another titanium compound, Japanese Patent Publication No. Sho 4
Japanese Patent Publication No. 8-2229 discloses titanium hydroxide.
No. 26597 discloses the use of α-titanic acid as a catalyst. However, in the former method, powdering of titanium hydroxide is not easy. On the other hand, in the latter method, α-titanic acid is liable to be deteriorated, and its storage and handling are not easy. Is not an appropriate method.

JP-B-59-46258 discloses a product obtained by reacting a titanium compound with trimellitic acid, and JP-A-58-38722 discloses a product obtained by reacting a titanium compound with a phosphite. It is disclosed that a product obtained by reacting is used as a catalyst. Certainly, according to this method, the color tone is improved, and the melting heat stability is improved to some extent, but it is not sufficient, and further improvement is desired.

Furthermore, Japanese Patent Application Laid-Open No. Hei 7-138354 proposes using a complex of a titanium compound and a phosphorus compound as a catalyst. According to this method, the color tone is improved, and the melting heat stability is improved to some extent. It improves, but not enough.

Incidentally, these titanium-phosphorus-based catalysts themselves often become foreign substances in the polyester polymer, and it has been desired to solve this problem.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a polyester which solves the above-mentioned problems of the prior art, has a good color tone, has a small amount of foreign matter, and has excellent fusion heat stability. Is to provide.

[0014]

Means for Solving the Problems The present inventors have made intensive studies in view of the above prior art, and as a result, have completed the present invention. That is, an object of the present invention is to polymerize a trimethylene glycol ester of a bifunctional aromatic carboxylic acid and / or a low polymer thereof or a tetramethylene glycol ester and / or a low polymer thereof in the presence of a titanium-based polycondensation catalyst. The following (a) to (b) obtained by a condensation reaction
In producing a polyester which simultaneously satisfies each of the requirements, a compound represented by the following general formula (I) and a phosphorus compound represented by the following general formula (II) are used as the titanium-based polycondensation catalyst. Atomic ratio (1/1)-
The compound obtained by the reaction in (3/1) is converted into a bifunctional aromatic carboxylic acid ethylene glycol ester and / or
Alternatively, it is achieved by a method for producing a polyester, characterized by adding 10 to 40 mmol% in terms of titanium atom based on all acid components constituting the low polymer. (A) The polyester was melted at 290 ° C. under vacuum for 10 minutes, and this was melted on an aluminum plate to a thickness of 3.0 ± 1.0 m.
Immediately after molding into a plate of m, the plate was quenched in ice water, and the plate was dried and crystallized at 160 ° C. for 1 hour. The L value measured using a total CR-200 is 80.0 or more, and the b value is -2.0 to 5.
Be in the range of 0. (B) It does not substantially contain a cobalt component.

[0015]

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[0016]

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[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method of the present invention will be described below in detail. Examples of the bifunctional aromatic carboxylic acid in the trimethylene glycol ester of the bifunctional aromatic carboxylic acid and / or the low polymer or the tetramethylene glycol ester and / or the low polymer thereof constituting the polyester of the present invention include, for example, ,Terephthalic acid,
Isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylmethanedicarboxylic acid, diphenyletherdicarboxylic acid, diphenoxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid, etc., and particularly terephthalic acid, naphthalenedicarboxylic acid It is preferred that

The above-mentioned trimethylene glycol ester of a bifunctional aromatic carboxylic acid and / or a low polymer thereof or a tetramethylene glycol ester and / or a low polymer thereof may be produced by any method. It is usually produced by reacting a difunctional aromatic carboxylic acid or an ester-forming derivative thereof with trimethylene glycol or tetramethylene glycol or an ester-forming derivative thereof by heating.

For example, the trimethylene glycol ester of terephthalic acid and / or its low polymer, which is a raw material of polytrimethylene terephthalate, will be described.
A method of directly esterifying terephthalic acid with trimethylene glycol, transesterifying a lower alkyl ester of terephthalic acid with ethylene glycol, or performing an addition reaction of terephthalic acid with trimethylene oxide is generally employed.

The effect of the present invention is substantially impaired by the above-mentioned trimethylene glycol ester of a bifunctional aromatic carboxylic acid and / or its low polymer or tetramethylene glycol ester and / or its low polymer. Other components that can be copolymerized may be contained in a range not to be limited, specifically, in a range of 10 mol% or less, preferably 5 mol% or less based on all acid components.

Other copolymerizable components preferably used include, as acid components, for example, aliphatic and alicyclic difunctional dicarboxylic acids such as adipic acid, sebacic acid and 1,4-cyclohexanedicarboxylic acid, and glycols. As a component, for example, an aliphatic, alicyclic, or aromatic diol compound such as an alkylene glycol having two or more constituent carbon atoms, 1,4-cyclohexanedimethanol, neopentyl glycol, bisphenol A, and bisphenol S, and a polydiol Examples of oxyalkylene glycol and hydroxycarboxylic acid include, for example, β-hydroxyethoxybenzoic acid, p-oxybenzoic acid, and the like.Each of these may be used alone or in combination of two or more.
There is no problem within the above copolymerization range.

In the production method of the present invention, a trimethylene glycol ester of a bifunctional aromatic carboxylic acid and / or a low polymer thereof or a tetramethylene glycol ester and / or a low polymer thereof is prepared in the presence of a titanium catalyst. A polyester is obtained by a polycondensation reaction,
In this case, the compound represented by the following general formula (I) and the phosphorus compound represented by the following general formula (II) as the polycondensation catalyst have a molar ratio of phosphorus / titanium atom of (1/1) to (3
/ 1) The compound obtained by the reaction in 1) is added in an amount of 10 to 40 mmol% in terms of titanium atom, based on the total acid components constituting the ethylene glycol ester of the bifunctional aromatic carboxylic acid and / or its low polymer. is necessary.

[0023]

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[0024]

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The compound represented by the general formula (I)
It may be simply abbreviated as compound (I). )as,
For example, titanium tetrabutoxide, titanium tetraisopropoxide, titanium tetrapropoxide, titanium tetraalkoxide such as titanium tetraethoxide, octaalkyl trititanate, hexaalkyl dititanate and the like, among which in the present invention From the viewpoint of reactivity with the phosphorus compound used, it is preferable to use titanium tetraalkoxide, and particularly preferable is titanium tetrabutoxide.

A compound represented by the general formula (II) (hereinafter simply referred to as compound (II)) reacted with compound (I)
May be abbreviated. ) Include phenylphosphonic acid, methylphosphonic acid, ethylphosphonic acid, propylphosphonic acid, isopropylphosphonic acid, butylphosphonic acid, tolylphosphonic acid, xylylphosphonic acid, biphenylylphosphonic acid, naphthylphosphonic acid, anthrylphosphonic acid, 2-carboxyphenylphosphonic acid, 3-carboxyphenylphosphonic acid, 4-carboxyphenylphosphonic acid, 2,3-dicarboxyphenylphosphonic acid,
2,4-dicarboxyphenylphosphonic acid, 2,5-dicarboxyphenylphosphonic acid, 2,6-dicarboxyphenylphosphonic acid, 3,4-dicarboxyphenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid,
2,3,4-tricarboxyphenylphosphonic acid, 2,
3,5-tricarboxyphenylphosphonic acid, 2,3
6-tricarboxyphenylphosphonic acid, 2,4,5-
Tricarboxyphenylphosphonic acid, 2,4,6-tricarboxyphenylphosphonic acid, diphenylphosphonic acid, bis (2-carboxyphenyl) phosphonic acid, bis (3-carboxyphenyl) phosphonic acid, bis (4-carboxyphenyl) phosphonic Acid, bis (2,3-dicarboxyphenyl) phosphonic acid, bis (2,4-dicarboxyphenyl) phosphonic acid, bis (2,5-dicarboxyphenyl) phosphonic acid, bis (2,6-dicarboxyphenyl) ) Phosphonic acid, bis (3,4-dicarboxyphenyl) phosphonic acid, bis (3,5-dicarboxyphenyl) phosphonic acid, bis (2,3,4-tricarboxyphenyl) phosphonic acid, bis (2,3 , 5-Tricarboxyphenyl) phosphonic acid, bis (2,3,6-tricarboxyphenyl) Suhon acid, bis (2,4,5-carboxyphenyl) phosphonic acid, bis (2,4,6
-Tricarboxyphenyl) phosphonic acid and the like, and particularly, phenylphosphonic acid, 3,5-dicarboxyphenylphosphonic acid, and diphenylphosphonic acid are preferably used.

When reacting the compound (I) with the compound (II), for example, the compound (II) is dissolved in a solvent.
After dissolving a part or all of the compound (I), the compound (I) is dissolved in the solvent.
May be dropped and reacted at a temperature of 0 ° C. to 200 ° C. for 30 minutes or more. At this time, the reaction pressure is not particularly limited, and the reaction can be performed under pressure, under normal pressure, or under reduced pressure.
Normal pressure is sufficient.

As the solvent, any solvent can be used as long as it can dissolve part or all of the compound (II). For example, ethanol, ethylene glycol, trimethylene glycol, tetramethylene glycol, benzene, Xylene or the like can be preferably used, but it is particularly preferable that the glycol component constituting the finally obtained polyester is reacted as a solvent, and the reaction is performed in a solution.

In this reaction, the reaction ratio between compound (I) and compound (II) is (1/1) to (3/1) in terms of a molar ratio of phosphorus / titanium atom. When the molar ratio is 1 /
If it exceeds 1, that is, if the proportion of the compound (I) is too large, the hue of the obtained polyester deteriorates, and the heat stability also decreases. On the other hand, when the molar ratio is less than 3/1, that is, when the ratio of the compound (I) is too small, the polycondensation reaction does not easily proceed. The molar ratio is preferably
(1.5 / 1) to (2.5 / 1).

In the production method of the present invention, the reaction product obtained by the above method is used as a titanium-based polycondensation catalyst to trimethylene glycol ester of a bifunctional aromatic carboxylic acid and / or its low polymer or tetramethylene glycol. The polycondensation reaction is carried out by adding the compound to a methylene glycol ester and / or its low polymer, and the reaction product is trimethylene glycol ester of a bifunctional aromatic carboxylic acid and / or its low polymer or tetramethylene glycol ester. And / or 10 to 10 in terms of titanium atoms, based on all the acid components constituting the low polymer thereof.
Add 40 mmol%. If the addition amount is less than 10 mmol%, the polycondensation reaction does not sufficiently proceed, and a polyester having a desired degree of polymerization cannot be obtained, or the polycondensation reaction becomes extremely slow, which is not preferable in terms of production efficiency. On the other hand, 40
If the amount exceeds mmol%, the hue of the obtained polyester, especially yellowish color, increases, and a molded product usable for use cannot be obtained.

The timing of the addition is determined before the start of the polycondensation reaction of the trimethylene glycol ester of the bifunctional aromatic carboxylic acid and / or its low polymer or the tetramethylene glycol ester and / or the low polymer. Any method may be used as long as it is an optional step, and any method known in the art can be used for the addition. For example, a method of adding a catalyst solution or slurry to the reaction system after completion of the first step reaction And the like.

The reaction product used as a catalyst is obtained by reacting compound (I) with compound (II),
The catalyst may be used as it is as a polyester polycondensation reaction catalyst, or may be used after recrystallization and purification with acetone or the like.

Further, in the production method of the present invention, the compound (I) and the compound (II) are represented by the following general formula (III) at an arbitrary stage before reacting the compound (I) and the compound (II). Reaction with an aromatic polycarboxylic acid or an anhydride thereof to obtain a titanium compound. Then, the titanium compound and the compound (II) are reacted in a molar ratio of phosphorus / titanium atom of (1/1) to (3 / It is preferable to use the compound obtained by the reaction in 1) as a polycondensation catalyst, because the hue of the obtained polyester is further improved.

[0034]

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The aromatic polycarboxylic acid represented by the general formula (III) or an anhydride thereof (hereinafter, may be simply abbreviated as compound (III)) is specifically phthalic. Acid, trimellitic acid, hemmellitic acid, pyromellitic acid and anhydrides thereof can be preferably used, and particularly from the viewpoint of the reactivity with the titanium compound and the affinity with the polyester when used as a catalyst. Preferably, an acid is used.

When reacting compound (I) with compound (III), part or all of compound (III) is dissolved in a solvent, and compound (I) is added dropwise.
The reaction may be performed at the above temperature for 30 minutes or more. The reaction pressure at this time is not particularly limited, and normal pressure is sufficient. As the solvent, any solvent can be used as long as it can dissolve part or all of the compound (III).
Preferred are ethylene glycol, trimethylene glycol, tetramethylene glycol, benzene, xylene and the like.

In this reaction, the molar ratio of the compound (I) to the compound (III) can be within a wide range. However, if the ratio of the compound (I) is too large, the color tone of the resulting polyester may deteriorate, The softening point tends to decrease. On the contrary, when the amount of the compound (I) is too small, the polycondensation reaction tends to be difficult to proceed. Therefore, the reaction ratio between the compound (I) and the compound (III) is (2/1) ~
(2/5) is preferable. The reaction product obtained by this reaction may be reacted with the compound (II) as it is, or may be recrystallized and purified with acetone or the like and then reacted with the compound (II).

The polyester obtained by the above production method has an L value of 80.0 obtained from a Hunter type colorimeter.
As described above, the b value is in the range of -2.0 to 5.0. here,
When the L value is less than 80.0, the molded product which can be used cannot be obtained because the whiteness is low. Also,
When the b value is less than -2.0, the yellowness is small, but the bluish color increases. On the other hand, when the b value exceeds 5.0, the yellowish color becomes strong, so that a molded product which can be similarly used can be obtained. I can't. The L value is preferably at least 82, particularly preferably at least 83, and the preferred range of the b value is -1.0 to 4.5, particularly preferably 0.0 to 4.0.

Note that the L value and the b value in the present invention are:
The measurement was performed according to the following method. That is, the polyester was melted at 290 ° C. under vacuum for 10 minutes, formed into a plate having a thickness of 3.0 ± 1.0 mm on an aluminum plate, and immediately quenched in ice water.
After drying and crystallization at 1 ° C. for 1 hour, the plate was placed on a white standard plate for adjusting a color difference meter, and the color tone of the plate surface was measured using a Hunter type color difference meter CR-200 manufactured by Minolta.

It is preferable that the polyester to be produced has a content of foreign matters having an average particle diameter of 3 μm or more of 500 particles / g or less. When the content is 500 or less,
Filter clogging during melt molding and increase in pack pressure during melt spinning are remarkably suppressed. The content is particularly preferably 400 pcs / g or less.

Further, the polyester produced is 250
It is desirable that the number of main chain breaks after heating and melting in a nitrogen atmosphere at 15 ° C. for 15 minutes is 4.0 eq / ton or less. When the number of main chain breaks is 4.0 eq / ton or less,
Since the deterioration during melt molding is remarkably suppressed, the mechanical properties and hue of the molded product are also improved.

The polyester to be produced contains substantially no cobalt atom. Polyester containing a cobalt atom has a problem that it has low melt heat stability and is liable to be decomposed. Here, “substantially” means that the cobalt atom is not contained as a coloring agent or a polycondensation catalyst.

The intrinsic viscosity of the polyester produced in the present invention is preferably in the range of 0.55 to 1.0. When the intrinsic viscosity is within this range, the strength of a molded product obtained by melt-molding the obtained polyester is sufficient,
In addition, the melt viscosity becomes too high, and the melt molding itself becomes difficult. A more preferred range of the intrinsic viscosity is 0.6
0 to 0.90, particularly preferably 0.62 to 0.8.
0.

In the production method of the present invention, a stabilizer such as trimethyl phosphate may be added at any stage in the production of the polyester, if necessary, and an antioxidant, an ultraviolet absorber, a flame retardant, a fluorescent brightening agent may be added. An agent, a matting agent, a coloring agent, an antifoaming agent and other additives may be blended.

Further, in order to finely adjust the color of the polyester, azo, triphenylmethane, quinoline, anthraquinone,
A coloring agent such as an organic blue pigment such as phthalocyanine or an inorganic blue pigment can be added. In the production method of the present invention, naturally, inorganic blue pigments containing cobalt, which is a toxic metal, are not used as a tinting agent, so that the resulting polyester is substantially free of cobalt. Become.

[0046]

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention. However, as described above, it is needless to say that the measurement of the hue, the number of foreign substances, and the stability of the fusion heat must be performed by the method described in this embodiment. Parts and% in Examples are parts by weight and% by weight unless otherwise specified.

(1) Intrinsic viscosity: Obtained from a value measured with an orthochlorophenol solution at 35 ° C. according to a conventional method.

(2) Color tone: 290
Melted under vacuum at 10 ° C for 10 minutes, formed into a plate having a thickness of 3.0 ± 1.0 mm on an aluminum plate, immediately cooled in ice water, and dried and crystallized at 160 ° C for 1 hour. Was placed on a white standard plate for adjusting a color difference meter, and the color tone of the plate surface was measured using a Hunter type color difference meter CR-200 manufactured by Minolta Co., Ltd. to obtain L and b values of the hunter. The L value indicates lightness, and the larger the numerical value, the higher the lightness, and the larger the b value, the greater the yellowness.

(3) Titanium content: The titanium concentration in the catalyst compound was determined using a fluorescent X-ray measuring apparatus 3270 manufactured by Rigaku Corporation.
The measurement was performed according to a conventional method.

(4) Melt heat stability (number of main chain cuts): Polyester pellets are 10 mm in outer diameter × 8 mm in inner diameter × 2 length
Place in a 50 mm glass test tube and place in a nitrogen atmosphere at 250
The polymer was immersed in a bath at 15 ° C. for 15 minutes, and the number of cuts (equivalents) of the polyester main chain per ton of the polyester polymer was determined from the difference in intrinsic viscosity before and after the test. The number of main chain breaks is determined by the following equation.

[0051]

(Equation 1)

(Where IV ₀ is the intrinsic viscosity before the heat treatment,
IV ₁ indicates intrinsic viscosity after heat treatment)

(5) Spinneret foreign matter: As an index of moldability, the obtained polyester was used as a chip, and this was used as a chip.
It was melted at 0 ° C., discharged from a spinneret having a hole diameter of 0.15 mmφ and 12 holes, spun at 600 m / min for 2 days, and the height of the foreign matter was measured. The larger the height, the more easily bending occurs, indicating that the polymer is inferior in moldability.

(6) Content of coarse particles in the polymer: 100 mg of the polymer was treated with 20 m of hexafluoroisopropanol.
1 μm, and the solution is 3 μm in aperture and 2.5 cm in diameter.
25% using a polytetrafluoroethylene membrane filter (“T300A” manufactured by ADVANTEC)
After filtration at 20 ° C. and 20 kPa, the number of coarse particles captured on the filter was counted by an optical microscope, and the content was converted into the content per 1 g of the polymer.

Example 1 (1) Preparation of catalyst (A): trimethylene glycol
After dissolving 0.8 part of trimellitic anhydride in 5 parts, 0.7 part of titanium tetrabutoxide (1/2 mol with respect to trimellitic anhydride) is added dropwise, and the mixture is maintained at 80 ° C. under normal pressure in the air for 60 minutes. The reaction was aged. After cooling to room temperature, 15 parts of acetone was added. 5 Filter with filter paper,
It was dried at 100 ° C. for 2 hours. The titanium content is 11.
It was 5% by weight. Also, trimethylene glycol 13
In 1 part, 3.6 parts of phenylphosphonic acid were dissolved at 120 ° C. for 10 minutes. This trimethylene glycol solution
After further adding 40 parts of trimethylene glycol to 5 parts, 5.0 parts of the above titanium compound was dissolved and stirred at 120 ° C. for 60 minutes to obtain a white slurry. The titanium content of this solution was 0.3%.

(2) Production of polyester: 166 parts of terephthalic acid and 92 parts of trimethylene glycol are subjected to an esterification reaction according to a conventional method, and the obtained product is placed in a polycondensation flask equipped with a rectification column and subjected to polycondensation. As a catalyst, 0.95 part of the catalyst (A) slurry obtained by the above operation (20 mmo in terms of titanium atom with respect to dimethyl terephthalate)
1%) and 0.000 of terazole blue as a tinting agent.
Add 02 parts, temperature 250 ° C, normal pressure for 30 minutes, further 4.0
After the reaction was allowed to proceed for 15 minutes under a reduced pressure of kPa, the pressure in the system was gradually reduced, and the reaction was allowed to proceed for 110 minutes with stirring. The final internal temperature was 250 ° C., the final internal pressure was 49.3 Pa, and the intrinsic viscosity of the obtained polytrimethylene terephthalate was 0.68.
It was 0. Table 1 shows the results.

[Examples 2 to 5, Comparative Examples 1 to 4] Example 1
In the production of polyester, the same operation was performed except that the molar ratio of phosphorus / titanium and the amount of catalyst added were changed as shown in Table 1. Table 1 shows the results.

Example 6 (1) Preparation of catalyst (B): trimethylene glycol 15
In 3 parts, 5.0 parts of phenylphosphonic acid were dissolved at 120 ° C. for 10 minutes. This trimethylene glycol solution
To 6 parts, 3.4 parts of titanium tetrabutoxide was added dropwise,
The mixture was stirred at 20 ° C. for 60 minutes to obtain a white slurry. The titanium content of this slurry was 0.3%. (2) Production of polyester: The same operation as in the production of the polyester of Example 1 was performed except that the catalyst (B) obtained by the above operation was used as the catalyst.
Table 1 shows the results.

Example 7 Production of polyester: 194 parts of dimethyl terephthalate
After putting 152 parts of trimethylene glycol and 0.12 parts of calcium acetate into a reaction vessel equipped with a rectification column, a transesterification reaction was carried out in accordance with a conventional method, and a theoretical amount of methanol was distilled off. In addition, the first stage reaction was completed. Next, the reaction product was put into a polycondensation flask equipped with a rectification column, and as a polycondensation catalyst, 3.2 parts of the catalyst (A) solution obtained by the operation of Example 1 (20 mmol as titanium relative to dimethyl terephthalate) %) And 0.0002 part of terazole blue as a color-matching agent, and added at a temperature of 250 ° C. under normal pressure for 30 minutes, and further under 4.0 kPa reduced pressure.
After the reaction was allowed to proceed for 5 minutes, the pressure inside the system was gradually reduced, and the reaction was carried out for 110 minutes with stirring. The final internal temperature was 250 ° C., the final internal pressure was 49.3 Pa, and the intrinsic viscosity of the obtained polytrimethylene terephthalate was 0.678. Table 1 shows the color tone and melt heat stability of the polymer.

Comparative Example 5 In the preparation of the polyester of Example 1, only titanium tetrabutoxide was used as the catalyst, and the concentration of the solution was adjusted so that the amount of the catalyst was 20 mmol% in terms of titanium atom with respect to dimethyl terephthalate. The same operation was performed except that the addition amount was adjusted. Table 1 shows the results.

Example 8 Production of Polyester: The same operation as in the production of the polyester of Example 7 was carried out except that the catalyst (B) solution obtained by the operation of Example 6 was added as a catalyst.
Table 1 shows the results.

Example 9 (1) Preparation of catalyst (C): After dissolving 0.8 part of trimellitic anhydride in 2.5 parts of tetramethylene glycol, 0.7 part of titanium tetrabutoxide (trimellitic anhydride) (1/2 mol with respect to the amount) was added dropwise, and the mixture was kept at 80 ° C. under normal pressure in the air and aged for 60 minutes. After cooling to room temperature, 15 parts of acetone was added. 5 Filtered with filter paper and dried at 100 ° C. for 2 hours. The titanium content was 11.5% by weight. Further, 3.6 parts of phenylphosphonic acid was added to 131 parts of tetramethylene glycol at 120 ° C.
For 10 minutes. After further adding 40 parts of tetramethylene glycol to 134.5 parts of this trimethylene glycol solution, 5.0 parts of the above titanium compound was dissolved, and 1 part of
The mixture was stirred at 20 ° C. for 60 minutes to obtain a white slurry. The titanium content of this solution was 0.3%.

(2) Preparation of polyester: 166 parts of terephthalic acid and 109 parts of tetramethylene glycol are subjected to an esterification reaction according to a conventional method, and the obtained product is placed in a polycondensation flask equipped with a rectification column, and subjected to polycondensation. As a catalyst, 0.95 part of the catalyst (A) slurry obtained by the above operation (20 m in terms of titanium atom with respect to dimethyl terephthalate)
mol%) and terrazole blue as a color matching agent.
After adding 0002 parts, the reaction was allowed to proceed at a temperature of 250 ° C. and normal pressure for 30 minutes, and further under a reduced pressure of 4.0 kPa for 15 minutes, and then the pressure inside the system was gradually reduced, and the reaction was allowed to proceed under stirring for 110 minutes. The final internal temperature was 250 ° C., the final internal pressure was 49.3 Pa, and the intrinsic viscosity of the obtained polybutylene terephthalate was 0.7.
00. Table 1 shows the results.

Comparative Example 6 (1) Preparation of Catalyst (D): After dissolving 0.80 part of trimellitic acid in ethanol, 0.64 part of titanium tetrabutoxide was added dropwise, and the mixture was dissolved in air at normal pressure. The mixture was kept at a temperature of 60 ° C. and aged for 60 minutes. After the reaction was aged, the mixture was cooled to room temperature, 15 parts of acetone was added, and the precipitate was collected by filtration. The titanium content of this precipitate was 12%. (2) Production of polyester: In the production of the polyester of Example 1, the catalyst (D) prepared by the above operation was used as a catalyst, and the amount of the catalyst was 20 mmol% in terms of titanium atom with respect to terephthalic acid. The same operation was performed except that the concentration and the addition amount of the catalyst solution were adjusted as much as possible. Table 1 shows the results.

Comparative Example 7 (1) Preparation of catalyst (E): Except that 3.6 parts of phenyl phosphite was used instead of 3.6 parts of phenylphosphonic acid in the method described in Example 1. The same operation was performed to prepare a catalyst, and a white slurry was obtained. The titanium content of this slurry was 0.3%. (2) Production of polyester: In the production of the polyester of Example 1, 3.2 parts of the catalyst (E) slurry obtained by the above operation (20 mmol% as titanium with respect to terephthalic acid) was used as a catalyst. Other than the above, the same operation was performed. Table 1 shows the results.

Comparative Example 8 The same operation as in Example 1 was carried out except that antimony trioxide was used as a catalyst and the amount of the catalyst was 25 mmol%. The results are shown in Table 1. As shown in FIG.

[0067]

[Table 1]

[0068]

According to the method of the present invention, it is possible to produce a polyester having an excellent color tone, a small amount of foreign substances in a polymer, and an excellent melt heat stability. This also has the effect that the amount of foreign matter in the base is extremely small and the moldability is excellent.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4J029 AA03 AB05 AC01 AC02 AD01 AE02 AE03 BA03 BA04 BA05 BA10 BB03A BB13A BD04A BH02 CB05A CB06A CB10A CC05A CC09 CE01 CF03 DB10 HA01 HA02 HB01 HB02 HD07 JB131 JC05 J0759B

Claims (2)

[Claims] 1. A polycondensation reaction of a trimethylene glycol ester of a bifunctional aromatic carboxylic acid and / or a low polymer thereof or a tetramethylene glycol ester and / or a low polymer thereof in the presence of a titanium-based polycondensation catalyst. In producing a polyester which simultaneously satisfies the following requirements (a) and (b), a compound represented by the following general formula (I) is used as the titanium-based polycondensation catalyst: ) With a phosphorus compound represented by the formula (1/1) to (3/1) in terms of a phosphorus / titanium atom molar ratio, to obtain a bifunctional aromatic carboxylic acid ethylene glycol ester and And / or adding 10 to 40 mmol% in terms of titanium atom based on all acid components constituting the low polymer thereof. Law. (A) The polyester was melted at 290 ° C. under vacuum for 10 minutes, and this was melted on an aluminum plate to a thickness of 3.0 ± 1.0 m.
Immediately after molding into a plate of m, the plate was quenched in ice water, and the plate was dried and crystallized at 160 ° C. for 1 hour. The L value measured using a total CR-200 is 80.0 or more, and the b value is -2.0 to 5.
Be in the range of 0. (B) It does not substantially contain a cobalt component. Embedded image Embedded image 2. As a titanium-based polycondensation catalyst, the compound represented by the following general formula (I) and the phosphorus compound represented by the following general formula (II) may be prepared in advance at any stage before the reaction. The compound of the general formula (I) and the following general formula (III)
Is reacted with an aromatic polycarboxylic acid or an anhydride thereof to obtain a titanium compound, and then the titanium compound and a phosphorus compound represented by the following general formula (II) are reacted in a molar ratio of phosphorus / titanium atom. The production method according to claim 1, wherein a compound obtained by reacting at a ratio of (1/1) to (3/1) is used. Embedded image Embedded image Embedded image