JP2001342332A - Method of manufacturing polyester and composition therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive to a polyester polymerization system which can avoid sudden boiling and a method of manufacturing polyesters using the same. SOLUTION: The composition mainly has an additive and polyester monomers whose major constituting component is bis-β-hydroxyethyl terephthalate, the additive accounting for 5-60 wt.% of the entire composition, and the method of manufacturing polyesters comprises adding this composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition suitable for addition to a polyester and a method for producing a polyester using the composition.

[0002]

2. Description of the Related Art Polyesters, particularly polyesters having polyethylene terephthalate as a main component, are extremely useful in various molded article fields such as fibers, films and resins, and are widely used. As a production method thereof, a bis-β-β-β-β-β-β-β-β derivative is directly reacted via a esterification reaction between terephthalic acid and ethylene glycol, or via a lower alkyl ester of terephthalic acid, particularly via a transesterification reaction between dimethyl terephthalate and ethylene glycol. −
At present, a method of subjecting an intermediate containing hydroxyethyl terephthalate to condensation polymerization at a high temperature and under a high vacuum as it is is currently practically used. In recent years, polyesters have been used in a wide variety of applications based on their excellent performance, and the performance requirements for polyesters have been diversified and advanced. In order to satisfy such demands, various attempts have been made to improve the properties by adding various additives in the production of polyester.

[0003] Polyethylene terephthalate is basically made to contain various metal compounds as a polymerization catalyst, and as described above, is maintained in a molten state under a high temperature and a high vacuum for a long time to increase the degree of polymerization. As a means for diversifying and upgrading such polyesters so as to satisfy various required qualities, conventionally, a method of adding a novel copolymer component or adding various additives to polyester has been proposed. When providing various additives to the polyester production process, quantitatively, smoothly, safely, etc., it is necessary to supply them to the system to meet various requirements for achieving the purpose,
It's not easy. For example, when the additive is a powder, it is necessary to remove an undesired gas such as oxygen taken into the powder when the system is in an inert atmosphere in order to be supplied directly into the system. This tends to cause a problem that the additive must be left in the additive container or that the additive remains in a non-negligible extent in the additive container. As a method of avoiding such a problem, for example, a method has been proposed in which the same liquid as that used as a raw material for polyester production such as ethylene glycol is used as a medium, and additives are dispersed or dissolved in the medium. I have. However, even with this method, it is difficult to maintain the uniformity in the added composition, because the temperature in the system is extremely high and significantly exceeds the boiling point of the medium, rapid boiling occurs during addition, which is dangerous. In addition, the inside of the system is cooled and solidified by the added material, which tends to cause problems such that the stirring cannot be performed uniformly or the stirring device may be damaged in some cases. Further, in order to avoid these problems, there has been proposed a method in which a high-boiling substance such as a certain plasticizer is used as a medium and measures such as preheating are taken.However, these mediums are difficult for polyester. It is not a drastic solution, as it is a foreign substance and causes problems that result in unintended consequences.

[0004]

Under such circumstances, the present inventors have conducted intensive studies on means suitable for supplying various additives to the polyester system. As a result, the present inventors have found that various additives can be dispersed or dissolved. As a result, they found that a composition using a polyester monomer as a medium to be provided in the system was suitable, and finally completed the present invention. An object of the present invention is to provide a composition in which various additives to a polyester are mixed into a polyester monomer, and which is suitable for being added during the production of the polyester. Still another object of the present invention is to provide a method for industrially advantageously producing a polyester containing various additives by adding the above composition of the present invention to a polyester production process. Still other objects and advantages of the present invention will become apparent from the following description.

[0005]

SUMMARY OF THE INVENTION The above objects and advantages of the present invention are as follows: first, an additive and a polyester monomer mainly composed of bis-.beta.-hydroxyethyl terephthalate, and the additive comprises Is 5-6 of the whole
Achieved by a composition that accounts for 0% by weight.

According to the present invention, the above objects and advantages of the present invention are, secondly, a combination of dialkyl terephthalate and ethylene glycol, a combination of terephthalic acid and ethylene glycol, and bis-β-hydroxyethyl terephthalate. In a method for producing a polyester using at least one selected from the group as a main raw material, in supplying an additive during the production process,
The additive is mainly composed of a polyester monomer having bis-β-hydroxyethyl terephthalate as a main component thereof, and the additive comprises 5 to 60% by weight of the total.
This is achieved by a method for producing a polyester, characterized in that it is supplied as a composition occupying

[0007] Also, according to the present invention, the above objects and advantages of the present invention are achieved, thirdly, by the use of the above composition of the present invention for adding additives to polyester during the polyester production process. Is done.

[0008] In the present invention, the polyester has ethylene terephthalate as a main constituent unit, and includes those obtained by copolymerizing at least one of other constituent components in a small proportion. The permissible range of the copolymer component is, for example, usually 40 mol% or less, preferably 3 mol% or less per total constitutional unit.
0 mol% or less, more preferably 20 mol% or less.
Examples of components that can be copolymerized include, as dicarboxylic acid components, for example, isophthalic acid, diphenyldicarboxylic acid,
Aromatic dicarboxylic acids such as diphenylsulfonedicarboxylic acid, diphenyletherdicarboxylic acid, naphthalenedicarboxylic acid, diphenoxyethanedicarboxylic acid and sodium sulfoisophthalic acid; aliphatic dicarboxylic acids such as sebacic acid and adipic acid; alicyclic rings such as hexahydroterephthalic acid Group dicarboxylic acids. Examples of diols include trimethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexane dimethanol, bis-β-hydroxyethyl bisphenol A, bis-β-hydroxyethoxydiphenyl sulfone, bis-β-hydroxyethoxydiphenyl ether, Examples thereof include diethylene glycol and polyethylene glycol. Also, there may be mentioned hydroxycarboxylic acids such as p-hydroxyethoxyphenylcarboxylic acid.
Furthermore, a combination of a trifunctional or higher polyfunctional compound and / or a monofunctional compound is also possible as long as the polyester maintains a linear shape. Examples of trifunctional or higher polyfunctional compounds include trimesic acid, glycerin, and pentaerythritol, and examples of monofunctional compounds include diphenylmonocarboxylic acid, diphenylether monocarboxylic acid, and phenoxy polyethylene glycol. These various copolymer components can be used as a functional derivative such as an ester. They are 1
It can be a species or two or more.

In the present invention, the polyester monomer is
Bis-β-hydroxyethyl terephthalate is the main constituent. The composition of the polyester monomer need not necessarily be the same as the composition of the polyester reaction system to which it is added. In the case of a system for producing polyethylene terephthalate, the polyester monomer added to the system is preferably bis-β-hydroxyethyl terephthalate. On the other hand, for example, a copolymer obtained by copolymerizing 10 mol% of isophthalic acid is used. If it is a system to be produced, the polyester monomer to be added to the system is isophthalate in 1
It can be a monomer containing 0 mole% or it can be bis-β-hydroxyethyl terephthalate. In the latter case, it is preferable to read the change in the amount of copolymerization due to the addition thereof and to preliminarily charge a large amount of the isophthalic acid component in the system. One of the effects obtained by the present invention is that the polyester monomer constituting the added composition has a high boiling point, so that the added composition avoids sudden boiling in the system environment. If the composition to be added is preliminarily heated, it is possible to prevent the inside of the system from being solidified by the addition. Another advantage obtained by the present invention is that the polyester monomer can be incorporated as part of the finished polyester without changing the quality.

The polyester monomer used in the present invention is
Constituting bis-β-hydroxyethyl terephthalate
Is preferably of high quality, especially
(I) Na, M
g, Ca, Fe, Co, Zn, Ti, Sn, Sb, Ge
And a cation consisting of P and (ii) halogen, N
O _Two, NO_Three, PO_FourAnd SO_FourTotal anions consisting of
Deionized to an ion content of 50 ppm or less
The crude bis-β-hydroxyethyl terephthalate is evaporated
Or purified bis-β- obtained by distillation purification
It is preferable to use hydroxyethyl terephthalate.
It is a new aspect. Bis-β-hydroxyethyl of low purity
When luterephthalate is used, the target polyether
Inferior steal quality or difficulties in manufacturing
This causes adverse effects and is not preferred. Such high-quality purified bis-
To obtain β-hydroxyethyl terephthalate practically
Is a crude bis-β-hydroxyethyl in such a special state.
Bis-β-hydroxye purified from terephthalate
To obtain tilterephthalate practically, evaporation under reduced pressure
Or it is necessary to carry out a distillation. Also, it
For practical implementation, crude bis-β-hydroxyethyl
Evaporation or distillation temperature of terephthalate evaporation or distillation
.Boiling or distillation under pressure, ie equilibrium evaporation
Or, instead of distillation, bis-β-hydroxy
Ciethyl terephthalate molecules substantially return to the evaporation surface
Unidirectional transfer of molecules from the evaporating surface to the condensing surface without returning
It is necessary to perform non-equilibrium evaporation or distillation where
Requires special evaporation or distillation means suitable for
You. Such an evaporation or distillation operation is generally referred to as molecular distillation.
It is sometimes called by its name.

Further, in order to carry out molecular distillation of the crude bis-β-hydroxyethyl terephthalate, the composition containing the crude bis-β-hydroxyethyl terephthalate before the molecular distillation is substantially decationized and / or dehydrated. Alternatively, it is necessary that the anion is deanionized and the total content of the specific cation and anion is not more than a certain amount. For this purpose, the crude bis-β-hydroxyethyl terephthalate is usually subjected to an ion exchange step as an ethylene glycol solution to be decationized and / or deanionized. Before and after that, if necessary, a decolorization step, crystallization, Through the process. If necessary, concentrate the substance having a lower boiling point than crude bis-β-hydroxyethyl terephthalate,
Practical means is subject to molecular distillation.

In the present invention, additives are added for the purpose of imparting some function to the polyester. Examples thereof include metal oxides represented by titanium dioxide, silicon trioxide, cobalt oxide, germanium oxide, zirconium oxide, aluminum oxide, antimony oxide, and zinc oxide; metal fine powders represented by silver, copper, and aluminum; Carbon black; inorganic pigments such as red iron oxide; and additives such as phthalocyanine-based, azo-based and benzophenone-based organic dyes and pigments. These may be surface-modified if necessary. These are used alone or in combination of two or more. For example, using anatase-type titanium dioxide to provide a matting effect when polyester is used for textile purposes, or for bottle applications using phthalocyanine blue as a pigment for imparting blue color and bengara as a pigment for imparting brown color. Typical examples include providing a coloring effect when the film is used, and providing a sliding effect by using silicon dioxide for a film application.

In the present invention, the additive accounts for 5 to 60% by weight of the whole composition. If the proportion of the additive is greater than this, the composition becomes unsatisfactory due to insufficient flowability when the composition is heated to liquefy the polyester monomer, and the proportion of the additive is less than this. In this case, the amount of the composition for imparting the above-described function to the polyester is excessively large, or the function cannot be sufficiently imparted. The presence of small proportions of other third substances in the composition, for example substances such as ethylene glycol and water, is acceptable as long as they do not significantly impair the intended use. The allowable ratio is usually about 2% by weight or less. If these third substances are present in an excessively large amount, for example, when ethylene glycol is present in a large amount such as 50% by weight, when this is added to the polyester production system, rapid boiling evaporation of ethylene glycol causes Problems such as blockage tend to occur, which is not preferable.

The present invention provides a composition comprising a combination of a dialkyl terephthalate and ethylene glycol, a combination of terephthalic acid and ethylene glycol, and / or
Alternatively, the present invention provides a method for producing a polyester by supplying bis-β-hydroxyethyl terephthalate as a main raw material to a polyester production process. The production of polyester by the combination of dialkyl terephthalate and ethylene glycol as referred to herein is sometimes called a transesterification method, and the production of polyester by the combination of terephthalic acid and ethylene glycol is sometimes called a so-called direct polymerization method. The present invention is applicable to any of these polymerization methods. Further, the present invention can be applied to a polymerization method using purified bis-β-hydroxyethyl terephthalate as at least a part of a raw material without any problem.

In such a case, the composition is supplied to the polyester production process at a stage until the production of the polyester is completed. If the supply stage is after the degree of polymerization of the polyester has significantly increased, the polyester monomer or the like in the composition may lower the degree of polymerization of the entire polyester, causing inconvenience. The feeding is preferably carried out around the time of the initiation of the polymerization, for example, in orthochlorophenol at a concentration of 0.1 g / ml and a reduced viscosity (ηsp / c) measured at 35 ° C. of about 0.15 to about 0.30. In addition, depending on the type of additive, uniformity may be extremely lost in the polyester production system depending on the timing of addition of the composition, so care must be taken. The supply of the composition to the polyester production step is preferably carried out in a state where the composition is heated and the polyester monomer is liquefied. In order to maintain the stability of the heated state of the composition,
The use of various stabilizers is acceptable. It is also acceptable to use an ultraviolet absorber for improving the light resistance of the polyester molded product.

[0016]

The present invention will be described in more detail with reference to the following examples. The present invention is not limited at all by the examples.

Example 1 A mixture of 1.04 mol of ethylene glycol to 1 mol of terephthalic acid, 0.03% by weight of antimony trioxide and 0.01% by weight of tributyl phosphite as phosphorus atom were added to the mixture. The mixed mixture was continuously supplied in a slurry state to the esterification reaction step. The first-stage esterification tank has a temperature of 258 ° C and a pressure of 500 KPa (kg
/ Cm ² G), the temperature of the second-stage esterification tank is 165 ° C.,
The reaction was carried out at normal pressure, and then sent to the first stage pre-polycondensation tank, operated at a temperature of 271 ° C and a pressure of 2 KPa (15 mmHg), and then sent to a final polycondensation machine via a filter at a temperature of 287 ° C. Operating at a pressure of 67 Pa (0.5 mmHg), 460 kg / h (11 tons / day) produces polyethylene terephthalate. On the other hand, a mixture of 40% by weight of pre-dried anatase type titanium dioxide and 60% by weight of bis-β-hydroxyethyl terephthalate was added to 12%.
After kneading at 4 ° C. in a jacketed kneader under a nitrogen seal, the resulting melt-kneaded product was filtered through a 0.5 μm filter and kept at 120 ° C. The melt-kneaded product containing titanium dioxide kept at 120 ° C. is stably continuously supplied to the first stage of the above-mentioned polyester production and prepolymerization tank at a ratio such that the product polyester contains 0.35% by weight of titanium dioxide. Was added.

The titanium oxide additive composition was supplied stably, and no increase in the pressure difference of the filter in the supply line from the second stage prepolymerization tank to the final polymerization tank was observed for 53 days. On the 53rd day, the filter was opened, and the adhesion of aggregates to the filter medium was extremely small. Further, when the dispersion state of titanium oxide in the obtained polyester pellet was formed into a film and observed in a dark field using a microscope, the dispersion state was extremely excellent and uniform.

Comparative Example 1 In Example 1, a mixture containing 50% by weight of titanium dioxide in ethylene glycol, which is a conventional method, was used in place of the melt-kneaded material containing titanium dioxide, and the mixture was treated with a pearl mill for 3 hours and centrifuged. After removing coarse particles with a machine, ethylene glycol was added to prepare a 20 wt% titanium dioxide suspension in ethylene glycol, and the suspension was filtered with a 0.5 μm filter. This suspension was continuously supplied to the second-stage esterification tank so as to have a concentration of 0.35% by weight in the polyester. As a result, the differential pressure of the filter in the supply line from the second stage pre-polycondensation to the final polycondensation reaction tank reaches the upper limit of 98 KPa (10 hg / cm ² ) on the 23rd day, and it is necessary to switch the filter. there were. In addition, coarse particles of light brown colored titanium dioxide were attached to the surface of the removed filter medium.

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Claims (7)

[Claims] 1. A composition comprising an additive and a polyester monomer mainly composed of bis-β-hydroxyethyl terephthalate, wherein the additive accounts for 5 to 60% by weight of the whole. . 2. A polyester monomer containing bis-β-hydroxyethyl terephthalate as a main component,
(I) Na, Mg, Ca, Fe, Co, Zn, Ti, S
a cation consisting of n, Sb, Ge and P and (i
i) 97% by weight or more obtained by subjecting crude bis-β-hydroxyethyl terephthalate having a total content of anions of halogen, NO ₂ , NO ₃ , PO ₄ and SO ₄ to 50 ppm or less to molecular distillation; The composition according to claim 1, having a bis-β-hydroxyethyl terephthalate content. 3. The composition according to claim 1, wherein the additive is one or more selected from the group consisting of metal oxides, fine metal powder, carbon black, inorganic pigments, and organic dyes and pigments. 4. A method for producing a polyester using at least one selected from the group consisting of a combination of dialkyl terephthalate and ethylene glycol, a combination of terephthalic acid and ethylene glycol, and bis-β-hydroxyethyl terephthalate as a main raw material. When the additives are supplied during the production process, the additives are mainly composed of a polyester monomer having bis-β-hydroxyethyl terephthalate as a main component, and the additive has a total weight of 5 to 60% by weight. % Of the composition, wherein the composition is supplied as a composition occupying the same percentage. 5. A polyester monomer containing bis-β-hydroxyethyl terephthalate as a main component,
(I) Na, Mg, Ca, Fe, Co, Zn, Ti, S
a cation consisting of n, Sb, Ge and P and (i
i) 97% by weight or more obtained by subjecting crude bis-β-hydroxyethyl terephthalate having a total content of anions consisting of halogen, NO ₂ , NO ₃ , PO ₄ and SO _{4 of not} more than 50 ppm to molecular distillation; The method for producing a polyester according to claim 4, which has a bis-β-hydroxyethyl terephthalate content ratio of 6. The method for producing a polyester according to claim 4, wherein the additive is one or more selected from the group consisting of metal oxides, fine metal powders, carbon black, inorganic pigments and organic dyes and pigments. 7. Use of the composition of claim 1 for adding additives to polyester during the polyester production process.