JP2018145413A - Production method of aliphatic aromatic polyester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a high quality aliphatic aromatic polyester having excellent color tone by suppressing by-production of tetrahydrofuran.SOLUTION: In a method of producing an aliphatic aromatic polyester by carrying out a polycondensation reaction by supplying an ester oligomer to a polycondensation reaction step after obtaining the ester oligomer by performing esterification and/or ester exchange reaction of an aliphatic diol component, an aliphatic dicarboxylic acid component and an aromatic dicarboxylic acid component under the presence of a catalyst, a terminal acid value of the ester oligomer is 30 to 1000 eq./ton, and before supplying the ester oligomer to the polycondensation step, the ester oligomer is contacted with a phosphorous compound.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for producing an aliphatic aromatic polyester using an aliphatic diol component, an aliphatic dicarboxylic acid component, and an aromatic dicarboxylic acid component as main raw materials. More specifically, the present invention relates to a method for producing an aliphatic aromatic polyester having good color tone by suppressing the by-product of tetrahydrofuran (THF).

  Various materials such as paper, plastic, and aluminum foil are used for various foods, medicines, miscellaneous liquids and granules, solid packaging materials, agricultural materials, and building materials. . Among them, plastics are excellent in strength, water resistance, moldability, transparency, cost, etc., and are therefore used in a wide range of applications as molded articles such as bags and containers. Currently, plastics widely used for applications such as bags and containers include polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyethylene terephthalate. However, molded articles made of the above-mentioned plastics do not biodegrade or hydrolyze in the natural environment, or the degradation rate is extremely slow, so when they are buried after use, they remain in the soil or are dumped. If this happens, the scenery may be damaged. Moreover, even when incinerated, there are problems such as generating harmful gases and damaging the incinerator.

  Biodegradable resins have been attracting attention as environmentally friendly plastics that solve these problems. Since the film formed by molding the biodegradable resin is decomposed in the soil by embedding in the soil after use, it is possible to prevent global warming and soil and air pollution. Therefore, in recent years, many biodegradable resin films are being used for garbage bags, shopping bags, and the like.

  However, since many of these biodegradable resin films are generally inferior in mechanical properties, many studies have been made to improve mechanical properties while maintaining good biodegradability. As a polyester having both properties, mechanical properties and moldability, an aliphatic diol such as 1,4-butanediol is used as the diol component, and an aliphatic dicarboxylic acid such as adipic acid and an aromatic such as terephthalic acid are used as the dicarboxylic acid component. An aliphatic aromatic polyester such as polybutylene adipate terephthalate (PBAT) obtained by using an aliphatic dicarboxylic acid in combination has been proposed.

  As with other polyesters, aliphatic aromatic polyesters such as PBAT are produced through an esterification step and a polycondensation step. In the esterification step, a titanium compound is mainly used as a catalyst. For example, Patent Document 1 describes that PBS was produced by performing an esterification step using a catalyst obtained by mixing a titanium compound, an alkaline earth metal, and a phosphorus compound in advance.

  Moreover, in patent document 2, after using a titanium catalyst in an esterification process, it inactivates before the polycondensation process with respect to the obtained esterification product (equivalent to the ester oligomer which concerns on this invention). It describes that PBAT was produced by adding a phosphorus compound as an agent or activator.

In the above Patent Document 1, a phosphorus compound is used as a catalyst for the production of PBS. However, a phosphorus compound previously mixed with a titanium compound or the like is prepared and added to the esterification step. After the esterification step, the addition position of the phosphorus compound is different from the present invention in which the phosphorus compound is added to the ester oligomer obtained by esterification.
In the conventional method, the terminal acid value of the ester oligomer generally obtained by esterification is controlled to be low. For example, Patent Document 1 does not disclose the acid value of the ester oligomer after the esterification step. The terminal carboxyl concentration of PBS after the polycondensation reaction is 23 eq. Therefore, it can be said that the terminal acid value of the ester oligomer in Patent Document 1 is lower than the terminal acid value defined in the present invention.
Moreover, in patent document 2, although there is no direct indication about the terminal acid value of the ester oligomer after an esterification process, the terminal acid value calculated from the data of an Example is 30 eq. The value is less than / ton.

JP 2008-45117 A Special table 2011-516708 gazette

When an aliphatic aromatic polyester such as PBAT is produced by the method described in Patent Document 1 or Patent Document 2, the resulting aliphatic aromatic polyester is colored red to pink, and the aliphatic aromatic polyester is molded. There is a problem that the molded product is reddish and inferior in quality.
Further, in the conventional method, 1,4-butanediol used as a raw material diol component is highly decomposable, tetrahydrofuran is easily generated as a by-product, and inefficient (such as 1,4-butanediol basic unit deterioration). is there.

  An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a method for producing a high-quality aliphatic aromatic polyester that suppresses by-production of tetrahydrofuran and has a good color tone.

  As a result of intensive studies to solve the above problems, the present inventors have undergone an esterification and / or transesterification reaction step in which an aliphatic diol component, an aliphatic dicarboxylic acid component, and an aromatic dicarboxylic acid component are reacted. Solving the above-mentioned problems by controlling the terminal acid value of the resulting ester oligomer within a predetermined range and bringing the phosphorus compound into contact with the ester oligomer whose terminal acid value is controlled, followed by a polycondensation reaction As a result, the present invention has been completed.

  That is, the gist of the present invention resides in the following [1] to [3].

[1] An ester oligomer is obtained by esterifying and / or transesterifying an aliphatic diol component, an aliphatic dicarboxylic acid component and an aromatic dicarboxylic acid component in the presence of a catalyst, and the ester oligomer is subjected to a polycondensation reaction step. In the method for producing an aliphatic aromatic polyester by feeding and performing a polycondensation reaction, the terminal acid value of the ester oligomer is 30 to 1000 eq. / Ton, and the ester oligomer is brought into contact with a phosphorus compound before the ester oligomer is supplied to the polycondensation reaction step.

[2] The method for producing an aliphatic aromatic polyester according to [1], wherein the alkaline earth metal compound is brought into contact with the ester oligomer together with the phosphorus compound.

[3] The method for producing an aliphatic aromatic polyester according to [2], wherein the alkaline earth metal compound is a magnesium compound.

  ADVANTAGE OF THE INVENTION According to this invention, the by-product of tetrahydrofuran can be suppressed and an aliphatic aromatic polyester with a favorable color tone can be manufactured, A high quality molded article can be provided using this polyester.

It is the schematic which shows one Embodiment of the esterification reaction process employ | adopted by this invention. It is the schematic which shows one Embodiment of the polycondensation process employ | adopted by this invention.

  Hereinafter, embodiments of the present invention will be described in detail. The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents unless it exceeds the gist.

  In the present specification, “mass%”, “mass ppm” and “part by mass” and “wt%”, “weight ppm” and “part by weight” have the same meaning, respectively.

  The process for producing an aliphatic aromatic polyester of the present invention comprises an ester diol obtained by esterifying and / or transesterifying an aliphatic diol component, an aliphatic dicarboxylic acid component and an aromatic dicarboxylic acid component in the presence of a catalyst. In the method for producing an aliphatic aromatic polyester by supplying the ester oligomer to a polycondensation reaction step and performing a polycondensation reaction, the terminal acid value of the ester oligomer is 30 to 1000 eq. / Ton, and the ester oligomer is brought into contact with a phosphorus compound before the ester oligomer is supplied to the polycondensation reaction step.

  Here, the “aliphatic dicarboxylic acid component” is a general term for aliphatic dicarboxylic acids used as polyester raw materials such as aliphatic dicarboxylic acid and aliphatic dicarboxylic acid derivatives such as aliphatic dicarboxylic acid alkyl ester, and “aromatic dicarboxylic acid”. “Component” is a general term for aromatic dicarboxylic acids that are used as polyester raw materials, such as aromatic dicarboxylic acid and aromatic dicarboxylic acid derivatives such as aromatic dicarboxylic acid alkyl esters. Hereinafter, the polyester produced by the method for producing an aliphatic aromatic polyester of the present invention may be referred to as “the aliphatic aromatic polyester of the present invention”.

  In the production method of the present invention, at least an aliphatic diol, an aliphatic dicarboxylic acid component and an aromatic dicarboxylic acid component are reacted as main raw materials in the presence of a catalyst, and an esterification and / or transesterification reaction step and subsequent polycondensation reaction Has a process, but "the aliphatic diol component, the aliphatic dicarboxylic acid component and the aromatic dicarboxylic acid component are the main raw materials" means that the diol component used as the raw material is mainly composed of the aliphatic diol component. This means that the dicarboxylic acid component used as a raw material is mainly composed of an aliphatic dicarboxylic acid component and an aromatic dicarboxylic acid component.

  Here, “having an aliphatic diol component as a main component” means “the total molar ratio of the aliphatic diol component is the largest among the raw material diol components”. Among these, from the viewpoint of physical properties and biodegradability of the polyester, the total of the aliphatic diol components is preferably 50 mol% or more, more preferably 60 mol% or more, and still more preferably based on the total of the raw material diol components. It is 70 mol% or more, and particularly preferably 90 to 100 mol%.

  In the present invention, each reaction step in producing the polyester can be carried out by a batch method or a continuous method. From the viewpoint of stabilization of quality and energy efficiency, the raw materials are continuously supplied and continuously. A so-called continuous method for obtaining polyester is preferred.

<Diol component>
As the diol component used in the present invention, as described above, at least the aliphatic diol component is used, and if the total molar ratio is most frequently used in the raw material diol, those usually used for the polyester raw material are used without particular limitation. can do.

Examples of the aliphatic diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7 -Oxygen such as heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, alkylene diol such as neopentyl glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol Examples thereof include cycloalkylene diols such as alkylene diol, 1,2-cyclohexane diol, 1,4-cyclohexane diol, 1,2-cyclohexane dimethanol, and 1,4-cyclohexane dimethanol. In view of the physical properties of the polyester to be produced, an alkylene diol having 6 or less carbon atoms such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, or a cyclohexane having 6 or less carbon atoms such as 1,4-cyclohexanedimethanol. Alkylene diols are preferable, and 1,4-butanediol is particularly preferable. Two or more of these may be used in combination. When 1,4-butanediol is used as the aliphatic diol component, the amount of 1,4-butanediol used is the total aliphatic diol from the viewpoint of the melting point (heat resistance), biodegradability, and mechanical properties of the resulting polyester. The amount is preferably 50 mol% or more, more preferably 70 mol% or more, particularly preferably 90 mol% or more, based on the components.
Among the aliphatic diol components, ethylene glycol, 1,3-propanediol, and 1,4-butanediol can be derived from plant materials.

<Dicarboxylic acid component>
As the dicarboxylic acid component used in the present invention, those usually used as raw materials for polyesters can be used without particular limitation.

Among the dicarboxylic acid components, examples of the aliphatic dicarboxylic acid component include oxalic acid, malonic acid, succinic acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecadicarboxylic acid. Examples include aliphatic dicarboxylic acids such as acid, dodecadicarboxylic acid and dimer acid, and hydrides of aromatic dicarboxylic acids such as hexahydrophthalic acid, hexahydroisophthalic acid and hexahydroterephthalic acid. From the viewpoint of physical properties, aliphatic dicarboxylic acids such as succinic acid, succinic anhydride, adipic acid, and sebacic acid, or derivatives thereof such as alkyl esters thereof are preferable, and particularly the reduction effect of tetrahydrofuran or the like according to the present invention and the improvement effect of hue are remarkable. Therefore, adipic acid is preferable. Two or more of these may be used in combination.
Among these aliphatic dicarboxylic acid components, succinic acid, succinic anhydride, adipic acid and the like can be derived from plant raw materials.

  When adipic acid is used as the aliphatic dicarboxylic acid component, the amount of adipic acid used is 50 moles relative to the total aliphatic dicarboxylic acid component from the viewpoint of the melting point (heat resistance), biodegradability and mechanical properties of the resulting polyester. % Or more, more preferably 70 mol% or more, and particularly preferably 90 to 100 mol%.

  Examples of the aromatic dicarboxylic acid component include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, furandicarboxylic acid, derivatives thereof such as alkyl esters thereof, and the like. Acid and isophthalic acid are preferable, and terephthalic acid is particularly preferable. These may be used alone or as a mixture of two or more.

  When terephthalic acid is used as the aromatic dicarboxylic acid component, the amount of terephthalic acid used is 50 mol% or more based on the total aromatic dicarboxylic acid component from the viewpoint of the melting point (heat resistance) and mechanical properties of the resulting polyester. It is preferably 70 mol% or more, particularly preferably 90 to 100 mol%.

  The ratio of the aliphatic dicarboxylic acid component and the aromatic dicarboxylic acid component in the total dicarboxylic acid component used in the present invention is aliphatic with respect to a total of 100 mol% of the aliphatic dicarboxylic acid component and the aromatic dicarboxylic acid component. The dicarboxylic acid component is preferably 30 to 70 mol% and the aromatic dicarboxylic acid component is preferably 30 to 70 mol%, particularly the aliphatic dicarboxylic acid component is 40 to 60 mol%, and the aromatic dicarboxylic acid component is 40 to 60 mol%. % Is preferable from the viewpoints of heat resistance, biodegradability, mechanical properties, and moldability.

<Other copolymer components>
The aliphatic aromatic polyester of the present invention may be copolymerized with other components other than the aliphatic diol component, the aliphatic dicarboxylic acid component, and the aromatic dicarboxylic acid component. Copolymerization components that can be used in this case include lactic acid, glycolic acid, hydroxybutyric acid, hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyiso Oxycarboxylic acids such as caproic acid, malic acid, maleic acid, citric acid, and fumaric acid, and esters, lactones, and oxycarboxylic acid polymers of these oxycarboxylic acids, or trifunctional groups such as glycerin, trimethylolpropane, and pentaerythritol The above polyhydric alcohols, or trifunctional or higher polyvalent carboxylic acids such as propanetricarboxylic acid, pyromellitic acid, trimellitic acid benzophenone tetracarboxylic acid, and anhydrides thereof, or the anhydride thereof can be used.

  Of these, tri- or higher-functional oxycarboxylic acids, tri- or higher-functional alcohols, tri- or higher-functional carboxylic acids, and the like can be easily obtained by adding a small amount of polyester. Among them, oxycarboxylic acids such as malic acid, citric acid and fumaric acid or polyhydric alcohols such as glycerin, trimethylolpropane and pentaerythritol are preferable, and trimethylolpropane is particularly preferable.

  In the case of using a trifunctional or higher polyfunctional compound, the amount used is preferably 0.001 to 5 mol%, more preferably 0.05 to 0.5 mol%, based on the total dicarboxylic acid component. . If the upper limit of this range is exceeded, gel (unmelted product) is likely to be formed in the obtained polyester, and if it is less than the lower limit, it is possible to increase the viscosity of the resulting polyester (usually by using a polyfunctional compound). ) Is difficult to obtain.

<Production method of polyester>
The method for producing the aliphatic aromatic polyester of the present invention will be described below by taking a continuous production method as an example. In the following, an example of a method for producing an aliphatic aromatic polyester by an esterification reaction step using an aliphatic diol, an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid and a subsequent polycondensation reaction step will be described. The process may be a transesterification reaction process, or a process of performing both esterification reaction and transesterification reaction.

  In the continuous production method, for example, aliphatic dicarboxylic acid and aromatic dicarboxylic acid and aliphatic diol are continuously used for a polyester pellet through a plurality of continuous reaction vessels, through an esterification reaction step and a melt polycondensation reaction step. However, as long as the effects of the present invention are not hindered, the method is not limited to the continuous method, and a conventionally known polyester production method can be employed.

<Esterification reaction process>
The esterification reaction step for reacting at least the dicarboxylic acid component and the diol component and the subsequent polycondensation reaction step can be carried out in a plurality of continuous reaction tanks or in a single reaction tank. In order to reduce the fluctuation of physical properties, it is preferable to carry out in a plurality of continuous reaction vessels.

  The reaction temperature in the esterification reaction step is not particularly limited as long as it is a temperature at which the esterification reaction can be performed, but is preferably 200 ° C. or higher, more preferably 210 ° C. in that the reaction rate can be increased. In order to prevent coloring of the polyester and the like, it is preferably 270 ° C. or lower, more preferably 260 ° C. or lower, and particularly preferably 250 ° C. or lower. If the reaction temperature is too low, the esterification reaction rate is slow, requiring a long reaction time, and undesirable reactions such as dehydration decomposition of aliphatic diols increase. If the reaction temperature is too high, the decomposition of aliphatic diol, aliphatic dicarboxylic acid and aromatic dicarboxylic acid will increase, and the amount of scattered matter will increase in the reaction tank, which may cause foreign matter and become turbid in the reaction product ( Haze) is likely to occur. The esterification temperature is preferably a constant temperature. The esterification rate is stabilized due to the constant temperature. The constant temperature is a set temperature ± 5 ° C., preferably ± 2 ° C.

  The reaction atmosphere is preferably an inert gas atmosphere such as nitrogen or argon.

  The reaction pressure is preferably 50 kPa to 200 kPa, more preferably 60 kPa or more, further preferably 70 kPa or more, more preferably 130 kPa or less, and still more preferably 110 kPa or less. If the reaction pressure is less than the above lower limit, the amount of scattered matter in the reaction tank increases, the haze of the reaction product becomes high and foreign substances increase easily, and the distillation of aliphatic diol to the outside of the reaction system increases and the polycondensation reaction rate increases. It tends to cause a decline. When the reaction pressure exceeds the above upper limit, the aliphatic diol is dehydrated and decomposed easily, and the polycondensation reaction rate tends to decrease.

  The reaction time is preferably 1 hour or longer, and the upper limit is preferably 10 hours or shorter, more preferably 4 hours or shorter.

  The reaction molar ratio of the aliphatic diol to the total of the aliphatic dicarboxylic acid and aromatic dicarboxylic acid to be subjected to the esterification reaction is determined based on the aliphatic dicarboxylic acid and aromatic dicarboxylic acid present in the gas phase and reaction liquid phase of the esterification reaction tank. And an aliphatic dicarboxylic acid that represents a molar ratio of an aliphatic diol and an esterified aliphatic diol to an esterified aliphatic dicarboxylic acid and an aromatic dicarboxylic acid, and that is decomposed in the reaction system and does not contribute to the esterification reaction, Aromatic dicarboxylic acids, aliphatic diols and their degradation products are not included. Examples of those that are decomposed and do not contribute to the esterification reaction include those in which 1,4-butanediol, which is an aliphatic diol, is decomposed into tetrahydrofuran, and tetrahydrofuran is not included in this molar ratio. In the present invention, the lower limit of the reaction molar ratio is usually 1.10 or more, preferably 1.12 or more, more preferably 1.15 or more, and particularly preferably 1.20 or more. The upper limit is usually 3.00 or less, preferably 2.50 or less, more preferably 2.30 or less, and particularly preferably 2.00 or less. If the reaction molar ratio is less than the above lower limit, the esterification reaction tends to be insufficient, and the polycondensation reaction, which is a reaction in the subsequent step, hardly proceeds, and it is difficult to obtain a polyester having a high degree of polymerization. When the reaction molar ratio exceeds the above upper limit, the decomposition amount of aliphatic diol, aliphatic dicarboxylic acid, and aromatic dicarboxylic acid tends to increase. In order to keep this reaction molar ratio within a preferable range, it is a preferable method to appropriately replenish the esterification reaction system with an aliphatic diol.

  In the present invention, the terminal acid value of the ester oligomer obtained in the esterification reaction step and supplied to the next polycondensation reaction is 30 to 1000 eq. / Ton. The terminal acid value of the ester oligomer is 30 eq. In order to make it lower than / ton, it is necessary to lengthen the esterification reaction or increase the reaction molar ratio, resulting in an increase in the amount of by-produced tetrahydrofuran. In addition, coloring due to deterioration of the terminal balance becomes significant. Conversely, the terminal acid value of the ester oligomer is 1000 eq. If it is higher than / ton, it causes inactivation of the polymerization due to catalyst precipitation and an increase in the amount of by-produced tetrahydrofuran due to acid. The terminal acid value supplied to the polycondensation reaction is 30 eq. / Eq is less than 1000 eq. Even if it exceeds / ton, the effect of the present invention cannot be obtained. In this invention, a terminal acid value is 30-1000 eq. In an esterification reaction process. / Ton ester oligomer is obtained, and the terminal acid value is 30 to 1000 eq. / Ton ester oligomer is brought into contact with the phosphorus compound before being supplied to the polycondensation reaction step, and then supplied to the polycondensation reaction step, thereby suppressing the by-production of tetrahydrofuran, reducing the purification load of the plant, and the color tone. A good aliphatic aromatic polyester can be obtained. In order to obtain the effect of the present invention more reliably, the terminal acid value of the ester oligomer is 50 to 800 eq. / Ton, preferably 100 to 500 eq. More preferably, it is / ton.

In order to control the terminal acid value of the ester oligomer within the above range, the reaction conditions such as the reaction molar ratio of the diol component to the dicarboxylic acid component, the reaction temperature, and the reaction pressure may be controlled. That is, when the reaction molar ratio of the diol component to the dicarboxylic acid component is lowered, the terminal acid value of the ester oligomer obtained tends to be low, and when it is reduced, the terminal acid value of the ester oligomer obtained tends to be high. Moreover, when the reaction temperature is increased and the reaction time is lengthened, the terminal acid value of the resulting ester oligomer tends to be low. Conversely, when the reaction temperature is lowered and the reaction time is shortened, the terminal acid value of the resulting ester oligomer is Since these conditions tend to be high, the terminal acid value of 30 to 1000 eq. / Ton ester oligomer can be obtained.
In addition, the terminal acid value of the ester oligomer can be controlled by appropriately setting the type and amount of catalyst used in the esterification reaction step described later.
In addition, the terminal acid value of ester oligomer is measured by the method as described in the term of the below-mentioned Example.

<Polycondensation reaction step>
In the method for producing an aliphatic aromatic polyester of the present invention, a polycondensation reaction is performed in a polycondensation reaction step following the esterification reaction step. In that case, in the manufacturing method of the aliphatic aromatic polyester of this invention, before supplying the ester oligomer obtained at the esterification reaction process to a polycondensation reaction process, it is made to contact with a phosphorus compound. Here, the phosphorus compound has a terminal acid value of 30 to 1000 eq. It is important that no phosphorus compound is present in the esterification reaction step. Moreover, it is preferable to make a phosphorus compound contact ester oligomer with an alkaline-earth metal compound.

The polycondensation reaction can be performed under reduced pressure using a plurality of continuous reaction vessels. Therefore, bringing the phosphorus compound into contact with the ester oligomer before the polycondensation reaction step corresponds to bringing the phosphorus compound into contact with the ester oligomer before the reduced pressure condition.
The lower limit of the reaction pressure in the final polycondensation reaction tank in the polycondensation reaction step is usually 0.01 kPa or more, preferably 0.03 kPa or more, and the upper limit is usually 1.4 kPa or less, preferably 0.4 kPa or less. If the pressure during the polycondensation reaction is too high, the polycondensation time will be prolonged, and accordingly, the molecular weight will be lowered or colored due to thermal decomposition of the polyester, which tends to make it difficult to produce a polyester exhibiting practically sufficient characteristics. On the other hand, the method of producing using an ultra-high vacuum polycondensation equipment with a reaction pressure of less than 0.01 kPa is a preferred embodiment from the viewpoint of improving the polycondensation reaction rate, but requires extremely expensive equipment investment. Therefore, it is economically disadvantageous.

  The lower limit of the reaction temperature is usually 215 ° C, preferably 220 ° C, and the upper limit is usually 270 ° C, preferably 260 ° C. If the reaction temperature is less than the above lower limit, the polycondensation reaction rate is slow, and not only does it take a long time to produce a polyester with a high degree of polymerization, but also a high power stirrer is required, which is economically disadvantageous. On the other hand, if the reaction temperature exceeds the above upper limit, thermal decomposition of the polyester during production tends to be caused, and it tends to be difficult to produce polyester having a high degree of polymerization.

  The lower limit of the reaction time is usually 1 hour, and the upper limit is usually 15 hours, preferably 10 hours, more preferably 8 hours. If the reaction time is too short, the reaction is insufficient and it is difficult to obtain a polyester having a high degree of polymerization, and the mechanical properties of the molded product tend to be inferior. On the other hand, if the reaction time is too long, the molecular weight drop due to the thermal decomposition of the polyester becomes remarkable, the mechanical properties of the molded product tend to be inferior, and the terminal amount of the carboxyl group that adversely affects the durability of the polyester is thermally decomposed. May increase due to

  A polyester having a desired intrinsic viscosity can be obtained by controlling the polycondensation reaction temperature and time and the reaction pressure.

<Reaction catalyst>
The reaction can be promoted by using a reaction catalyst for the esterification reaction and the polycondensation reaction. When a catalyst is used, the haze of the resulting polyester may increase when the catalyst is added to the gas phase part of the reaction vessel, and the catalyst may be converted into a foreign substance.

In the polycondensation reaction, it is difficult to proceed without a catalyst, and therefore a catalyst is preferably used. The polycondensation reaction catalyst may be added at any stage between the esterification reaction step and the polycondensation reaction step. Moreover, you may add a polycondensation reaction catalyst in multiple times between an esterification reaction process and a polycondensation reaction process.
As the polycondensation reaction catalyst, a compound containing at least one of the metal elements of Groups 1 to 14 of the periodic table is generally used. Specific examples of metal elements include scandium, yttrium, samarium, titanium, zirconium, vanadium, chromium, molybdenum, tungsten, tin, antimony, cerium, germanium, zinc, cobalt, manganese, iron, aluminum, magnesium, calcium, Examples include strontium, sodium and potassium. Among them, scandium, yttrium, titanium, zirconium, vanadium, molybdenum, tungsten, zinc, iron, and germanium are preferable, and titanium, zirconium, tungsten, iron, and germanium are particularly preferable. Furthermore, in order to reduce the polyester terminal density | concentration which affects the thermal stability of polyester, among the said metals, the periodic table 3-6 group metal element which shows Lewis acidity is preferable. Specifically, scandium, titanium, zirconium, vanadium, molybdenum, and tungsten are preferable, and titanium and zirconium are particularly preferable from the viewpoint of availability, and titanium is more preferable from the viewpoint of reaction activity.
Here, the periodic table refers to a long-period periodic table (Nomenclature of Inorganic Chemistry IUPAC Recommendations 2005).

  In the present invention, a titanium compound is preferably used as a catalyst in the esterification reaction step.

  As the titanium compound, tetraalkyl titanate and a hydrolyzate thereof are preferable. Specifically, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-t-butyl titanate, tetraphenyl titanate, Examples include tetracyclohexyl titanate, tetrabenzyl titanate and mixed titanates thereof, and hydrolysates thereof.

  In addition, titanium (oxy) acetylacetonate, titanium tetraacetylacetonate, titanium (diisoproxide) acetylacetonate, titanium bis (ammonium lactate) dihydroxide, titanium bis (ethylacetoacetate) diisopropoxide, titanium (triethanolaminate) ) Isopropoxide, polyhydroxytitanium stearate, titanium lactate, titanium triethanolamate, and butyl titanate dimer are also preferably used.

  Among these, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, titanium (oxy) acetylacetonate, titanium tetraacetylacetonate, titanium bis (ammonium lactate) dihydroxide, polyhydroxytitanium stearate Rate, titanium lactate, butyl titanate dimer are preferred, tetra-n-butyl titanate, titanium (oxy) acetylacetonate, titanium tetraacetylacetonate, polyhydroxy titanium stearate, titanium lactate, butyl titanate dimer are more preferred, Tetra-n-butyl titanate, polyhydroxytitanium stearate, titanium (oxy) acetylacetonate, and titanium tetraacetylacetonate are preferred.

  These titanium compounds include alcohols such as methanol, ethanol, isopropanol and butanol, diols such as ethylene glycol, butanediol and pentanediol, ethers such as diethyl ether and tetrahydrofuran, nitriles such as acetonitrile, heptane, toluene, etc. Using a solvent for dissolving the catalyst such as a hydrocarbon compound, water, and a mixture thereof, the catalyst solution is usually supplied to the esterification reaction step as a catalyst solution prepared so that the titanium compound concentration is 0.05 to 5% by weight. The

  Further, the terminal acid value obtained in the esterification reaction step is 30 to 1000 eq. Specific examples of the phosphorus compound to be brought into contact with the ester oligomer of / ton include, for example, orthophosphoric acid, polyphosphoric acid, and trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, trioctyl phosphate, triphenyl phosphate, Tricresyl phosphate, tris (triethylene glycol) phosphate, ethyl diethyl phosphonoacetate, methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, monobutyl phosphate, dibutyl phosphate, dioctyl phosphate, triethylene glycol acid phosphate Pentavalent phosphorus compounds such as phosphorous acid, hypophosphorous acid, diethyl phosphite, trisdodecyl phosphite , Tris nonyl decyl phosphite, trivalent phosphorus compounds such as triphenyl phosphite and the like. Among them, acidic phosphoric acid ester compounds are preferred, and acidic phosphoric acid ester compounds having an ester structure of phosphoric acid having at least one hydroxyl group represented by the following general formula (I) and / or (II) Is preferably used.

(Wherein R, R ′ and R ″ each represent an alkyl group having 1 to 6 carbon atoms, a cyclohexyl group, an aryl group or a 2-hydroxyethyl group. In formula (I), R and R ′ are the same. It may or may not be.)

  Specific examples of such acidic phosphate ester compounds include methyl acid phosphate, ethyl acid phosphate, isopropyl acid phosphate, butyl acid phosphate, octyl acid phosphate, and the like, and ethyl acid phosphate and butyl acid phosphate are preferred. These acidic phosphate ester compounds may be used alone or in combination of two or more.

  In addition, although there exist monoester body (II) and diester body (I) in an acidic phosphoric ester compound, since the catalyst which shows high catalyst activity is obtained, a monoester body or a monoester body and a diester body It is preferable to use a mixture. The mixing weight ratio of monoester and diester (monoester: diester) is preferably 80 or less: 20 or more, more preferably 70 or less: 30 or more, and particularly preferably 60 or less: 40 or more. Also, it is preferably 20 or more and 80 or less, more preferably 30 or more and 70 or less, and particularly preferably 40 or more and 60 or less.

  Further, in the present invention, it is preferable to contact an alkaline earth metal compound with an ester oligomer together with these phosphorus compounds. Examples of the alkaline earth metal compound include various compounds of beryllium, magnesium, calcium, strontium, and barium. Magnesium and calcium compounds are preferred from the viewpoints of handling and availability, and catalytic effects, and among them, magnesium compounds having excellent catalytic effects are preferred. Specific examples of the magnesium compound include magnesium acetate, magnesium hydroxide, magnesium carbonate, magnesium oxide, magnesium alkoxide, magnesium hydrogen phosphate, and the like. Among these, magnesium acetate is preferable.

  These phosphorus compounds and alkaline earth metal compounds are prepared by using the solvent exemplified as the solvent for dissolving the catalyst used in the preparation of the catalyst solution of the titanium compound described above. It is preferable to add to the ester oligomer supplied to the polycondensation reaction step as a catalyst solution prepared so that the metal compound has a concentration of 0.02 to 9.7% by weight.

  In addition, although there is no restriction | limiting in particular about the usage-amount of a titanium compound used at an esterification reaction process, and the phosphorus compound and alkaline-earth metal compound used at a polycondensation reaction process, For example, a titanium compound is Ti with respect to a production | generation polymer. It is preferable to use it so that it may become 5-100 weight ppm in conversion addition amount. The phosphorus compound is used so that the P conversion addition molar ratio (P / Ti molar ratio) to the Ti conversion addition molar amount of the titanium compound is 0.5 to 2.5, and the alkaline earth metal compound is a titanium compound. It is preferable that the alkaline earth metal equivalent addition molar ratio (alkaline earth metal / Ti molar ratio) to the Ti equivalent addition molar amount is 0.5 to 3.0. If any of the catalyst compounds is too much, it is not only economically disadvantageous, but the reason is not yet clear, but the terminal acid value in the finally obtained polyester may be increased. In addition, the thermal stability and hydrolysis resistance of the polyester may decrease due to an increase in the residual catalyst concentration. On the other hand, if the amount is too small, the reaction activity is lowered, and accordingly, thermal decomposition of the polyester is induced during the production of the polyester, making it difficult to obtain a polyester having practically useful physical properties.

<Reaction tank>
As the esterification reaction tank used in the present invention, known ones can be used, and any of a vertical stirring complete mixing tank, a vertical heat convection mixing tank, a tower type continuous reaction tank, etc. may be used. A single tank or a plurality of tanks in which similar or different tanks are connected in series may be used. Among them, a reaction tank having a stirrer is preferable. As a stirrer, in addition to a normal type including a power unit, a receiver, a shaft, and a stirring blade, a turbine stator type high-speed rotary stirrer, a disk mill type stirrer, a rotor mill type stirrer, etc. The type that rotates at a high speed can also be used.

  There is no limitation on the form of stirring, and in addition to the normal stirring method in which the reaction liquid in the reaction tank is directly stirred from the top, bottom, side, etc. of the reaction tank, a part of the reaction liquid is piped outside the reaction tank, etc. It is possible to take a method of circulating the reaction liquid by taking it out with a line mixer and the like. Known types of stirring blades can be selected, and specific examples include propeller blades, screw blades, turbine blades, fan turbine blades, disk turbine blades, fouller blades, full zone blades, Max blend blades, and the like.

  There is no restriction | limiting in particular in the type of the polycondensation reaction tank used for this invention, For example, a vertical stirring polymerization tank, a horizontal stirring polymerization tank, a thin film evaporation type polymerization tank etc. can be mentioned. The number of polycondensation reaction tanks can be one, or a plurality of tanks of the same or different types can be connected in series. It is preferable to select a horizontal stirring polymerization machine having a thin film evaporation function excellent in renewability, plug flow property, and self-cleaning property.

<Example of manufacturing process>
Hereinafter, based on the drawings, adipic acid as an aliphatic dicarboxylic acid, terephthalic acid as an aromatic dicarboxylic acid, 1,4-butanediol as an aliphatic diol, and a method for producing a polyester using malic acid as a polyfunctional compound are preferable. Although an embodiment is described, the present invention is not limited to this.

  FIG. 1 is an explanatory diagram of an example of an esterification reaction step employed in the present invention, and FIG. 2 is an explanatory diagram of an example of a polycondensation step employed in the present invention.

  In FIG. 1, the raw materials adipic acid, terephthalic acid and malic acid are usually mixed with 1,4-butanediol in a raw material mixing tank (not shown), and in the form of slurry or liquid from the raw material supply line (1). It supplies to an esterification reaction tank (A). Moreover, when adding a catalyst at the time of esterification, after making it the solution of 1, 4- butanediol in a catalyst adjustment tank (not shown), a catalyst solution is supplied from a catalyst supply line (3). In FIG. 1, the catalyst supply line (3) is connected to the recirculation line (2) of the recirculated 1,4-butanediol, and both are mixed and then supplied to the liquid phase part of the esterification reaction tank (A). showed that.

  The gas distilled from the esterification reaction tank (A) is separated into a high-boiling component and a low-boiling component in the rectifying column (C) through the distillation line (5). Usually, the main component of the high boiling point component is 1,4-butanediol, and the main component of the low boiling point component is water and tetrahydrofuran (THF) which is a decomposition product of 1,4-butanediol.

  The high-boiling components separated in the rectification column (C) are extracted from the extraction line (6), passed through the pump (D), and partly from the recirculation line (2) to the esterification reaction tank (A). It is circulated and part is returned from the circulation line (7) to the rectification column (C). Further, the surplus is extracted outside from the extraction line (8). On the other hand, the light boiling components separated in the rectification column (C) are extracted from the gas extraction line (9), condensed in the condenser (G), and temporarily passed through the condensate line (10) to the tank (F). Can be stored. A part of the light boiling components collected in the tank (F) is returned to the rectification column (C) through the extraction line (11), the pump (E) and the circulation line (12), and the remainder is extracted. It is extracted outside through the line (13). The condenser (G) is connected to an exhaust device (not shown) via a vent line (14). The ester oligomer, which is the esterification reaction product generated in the esterification reaction tank (A), passes through the extraction pump (B) and the extraction line (4) of the ester oligomer (1st polycondensation reaction tank ( a).

  In the process shown in FIG. 1, the catalyst supply line (3) is connected to the recirculation line (2), but both may be independent. Moreover, the raw material supply line (1) may be connected to the liquid phase part of the esterification reaction tank (A).

  The catalyst is added to the ester oligomer to be subjected to the polycondensation reaction, for example, after a catalyst solution containing a phosphorus compound, preferably a phosphorus compound and an alkaline earth metal compound, is prepared to a predetermined concentration in a catalyst preparation tank (not shown). 2 is supplied to the raw material supply line (L8) through the catalyst supply line (L7) in FIG. 2, further diluted with 1,4-butanediol, and then supplied to the ester oligomer extraction line (4). .

  The ester oligomer supplied from the ester oligomer extraction line (4) to the first polycondensation reaction tank (a) is polycondensed under reduced pressure to become a polyester low polymer, and then the extraction gear pump (c) and It supplies to a 2nd polycondensation reaction tank (d) through an extraction line (L1). In the second polycondensation reaction tank (d), the polycondensation reaction usually proceeds further at a lower pressure than in the first polycondensation reaction tank (a). The obtained polycondensate is supplied to the third polycondensation reaction tank (k) through the extraction gear pump (e) and the extraction line (L3) as the outlet channel. The third polycondensation reaction tank (k) is a horizontal reaction tank composed of a plurality of stirring blade blocks and equipped with a biaxial self-cleaning type stirring blade. The polycondensation reaction product introduced from the second polycondensation reaction tank (d) to the third polycondensation reaction tank (k) through the extraction line (L3) is further pelletized after the polycondensation reaction is further advanced here. It is transferred to the process.

  In the pelletizing step, the melted polyester is cut with an underwater cutter (h) through an extraction gear pump (m) and a filter (n) which is an outlet channel to obtain polyester pellets. In addition, after extracting a melt strand in air | atmosphere and cooling with water etc., you may cut | disconnect with a rotary cutter and pelletize.

  Reference numerals (L2), (L4), and (L6) in FIG. 2 denote vents of the first polycondensation reaction tank (a), the second polycondensation reaction tank (d), and the third polycondensation reaction tank (k), respectively. Line. Note that filters may be provided on the lines (4), (L1), (L3), and (L5).

<Physical properties of polyester>
The lower limit of the intrinsic viscosity (IV) of the aliphatic aromatic polyester of the present invention obtained by the present invention is preferably 1.0 dL / g or more, particularly preferably 1.2 dL / g or more. The upper limit of the intrinsic viscosity of the polyester is preferably 2.5 dL / g, more preferably 2.2 dL / g, and particularly preferably 2.0 dL / g. When the intrinsic viscosity is less than the lower limit, it is difficult to obtain sufficient mechanical strength when formed into a molded product. If the intrinsic viscosity exceeds the upper limit, the melt viscosity is high during molding and molding is difficult.

  The terminal acid value of the aliphatic aromatic polyester of the present invention is usually 80 eq. / Ton or less, preferably 60 eq. / Ton or less, more preferably 50 eq. / Ton or less. When the terminal acid value of the aliphatic aromatic polyester exceeds the above upper limit, the viscosity decrease due to hydrolysis becomes remarkable, and the quality may be significantly impaired. The lower the terminal acid value, the better the thermal stability and hydrolysis resistance, but the terminal acid value of the aliphatic aromatic polyester obtained by the present invention is usually 20 eq. / Ton or more, more preferably 25 eq. / Ton or more, especially 30 eq. / Ton or more is preferable.

<Polyester composition>
You may mix | blend aliphatic polyester, aliphatic oxycarboxylic acid, etc. with the aliphatic aromatic polyester of this invention obtained by this invention. Furthermore, carbodiimide compounds, fillers, plasticizers, and other biodegradable resins that are used as necessary, such as polycaprolactone, polyamide, polyvinyl alcohol, cellulose ester, etc. Cellulose, paper, wood powder, chitin / chitosan, animal / plant substance fine powder such as coconut shell powder, walnut shell powder, or a mixture thereof can be blended. Furthermore, additives such as heat stabilizers, plasticizers, lubricants, anti-blocking agents, nucleating agents, inorganic fillers, colorants, pigments, ultraviolet absorbers, light stabilizers, etc. are used for the purpose of adjusting the physical properties and processability of the molded products. Further, a modifier, a crosslinking agent, etc. may be included.

  The method for producing the polyester composition from the aliphatic aromatic polyester of the present invention is not particularly limited, but is a method in which raw material chips of the blended polyester are melt-mixed in the same extruder, and each is melted in separate extruders. Examples of the mixing method include single-screw extruder, twin-screw extruder, Banbury mixer, roll mixer, Brabender plastograph, kneader blending by kneading using a kneader blender. In addition, it is possible to obtain a molded body at the same time as preparing a composition by directly supplying each raw material chip to a molding machine.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example at all unless the summary is exceeded.

  In addition, the measuring method of the physical property and evaluation item which were employ | adopted in the following examples is as follows.

<Intrinsic viscosity (IV) dL / g>
Using an Ubbelohde viscometer, it was determined as follows. That is, a mixed solvent of phenol / tetrachloroethane (mass ratio 1/1) was used, and at 30 ° C., the polymer solution having a concentration of 0.5 g / dL and the number of falling seconds of the solvent alone were measured, and the following formula (1) I asked more.
IV = ((1 + 4K _H η _SP ) ^0.5 −1) / (2K _H C) (1)
Where η _SP = η / η ₀ −1, η is the sample solution fall seconds, η ₀ is the solvent drop seconds, C is the sample solution concentration (g / dL), and K _H is the Huggins constant. . K _H adopted the 0.33.

<Terminal acid value of ester oligomer eq. / Ton>
0.3 g of pasty ester oligomer was collected in a 100 mL beaker, 40 mL of benzyl alcohol was added, and the mixture was heated on a hot plate at 180 ° C. while blowing dry nitrogen gas. The temperature was lowered to 60 ° C. by water cooling after 20 minutes while confirming dissolution on the way. Rinse the oil droplets on the beaker wall with 10 mL of benzyl alcohol, add 1 to 2 drops of phenol red indicator to this solution, and stir while blowing dry nitrogen gas with 0.1 mol / L potassium hydroxide in methanol. The titration was completed when the color changed from yellow to red. Moreover, the same operation was implemented only with benzyl alcohol as a blank, and the terminal acid value (terminal carboxy group amount) was computed by the following formula | equation (2).

<Terminal acid value of polyester eq. / Ton>
The pelletized polyester was dried at 60 ° C. for 8 hours in a vacuum dryer and cooled to room temperature in a desiccator, 0.5 g was accurately weighed and collected in a test tube, and 25 mL of benzyl alcohol was added. The solution was dissolved at 195 ° C. for 3 minutes while blowing dry nitrogen gas. Next, after cooling and stirring in an ice bath for 40 seconds, 2 mL of ethanol was gradually added. Add 1 to 2 drops of phenol red indicator to this solution, and titrate with 0.1 mol / L sodium benzyl alcohol solution of sodium hydroxide with stirring while blowing dry nitrogen gas. did. Moreover, the same operation was implemented as a blank, without adding a polyester sample, and the terminal acid value (terminal carboxy group amount) was computed by the following formula | equation (2).

<Calculation formula of terminal acid value>
Terminal acid value (eq./ton)=(ab)×0.1×f/w (2)

Here, a is the amount of benzyl alcohol solution of 0.1 mol / L sodium hydroxide required for titration (μL), b is benzyl of 0.1 mol / L sodium hydroxide required for titration with a blank. The amount of alcohol solution (μL), w is the amount of ester oligomer or polyester sample (g), and f is the titer of a 0.1 mol / L sodium hydroxide benzyl alcohol solution.
The titer (f) of a benzyl alcohol solution of 0.1 mol / L sodium hydroxide was determined by the following method.
Collect 5 cm ³ of methanol in a test tube and add 1-2 drops as an indicator of phenol red in ethanol solution. Titration to a discoloration point with 0.4 cm ³ of benzyl alcohol solution of 1 mol / L sodium hydroxide, and then adding 0.2 cm ³ of 0.1 mol / L aqueous hydrochloric acid solution with known titer as a standard solution, and again, The solution was titrated to a discoloration point with a 0.1 mol / L sodium hydroxide solution in benzyl alcohol (the above operation was performed while blowing dry nitrogen gas). And titer (f) was computed by the following formula | equation (3).
Titer (f) = titer of 0.1 mol / L hydrochloric acid aqueous solution x sampling amount of 0.1 N hydrochloric acid aqueous solution (µL) / titration amount of benzyl alcohol solution of 0.1 mol / L sodium hydroxide (µL) ... (3)

<Yellowness (YI)>
It measured based on the method of JISK7373. This value is preferably as low as possible, and is preferably 40 or less in the present invention.

[Example 1]
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a vacuum outlet, 100 parts by weight of adipic acid, 101 parts by weight of terephthalic acid, 202 parts by weight of 1,4-butanediol, 1, 1.92 parts by weight of a tetra-n-butyl titanate solution prepared to a concentration of 3% by weight with 4-butanediol was added, and the system was placed in a nitrogen atmosphere by nitrogen-reduced pressure substitution. While stirring the system, the temperature was raised to 230 ° C. over 1 hour, and the reaction was carried out at this temperature for 2 hours and 30 minutes. The terminal acid value of the obtained ester oligomer was measured and found to be 102 eq. / Ton.

  To this ester oligomer, 9.75 parts by weight of a 1,4-butanediol solution prepared to have an ethyl acid phosphate concentration of 0.4% by weight and a magnesium acetate concentration of 0.6% by weight was added.

  Next, while stirring the system at 150 rpm, the temperature was raised to 250 ° C. over 30 minutes, and the pressure was reduced to 70 Pa at the same time, and the stirring rotation speed of the stirring device after the pressure reduction was lowered stepwise to 150 rpm, 60 rpm, 40 rpm, and 20 rpm. It was. When the torque value reached 0.2 N · m at 20 rpm, the contents were extracted as a strand from the bottom of the reaction vessel at 230 ° C. and submerged in 10 ° C. water, and then the strand was cut with a cutter. White pellets were obtained by heating and drying at 60 ° C. for 8 hours under vacuum.

  The obtained pellet had a yellowness (YI) of -3 and a terminal acid value of 44 eq. / Ton, the intrinsic viscosity was 1.38 dL / g.

[Example 2]
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a vacuum outlet, 100 parts by weight of adipic acid, 101 parts by weight of terephthalic acid, 163 parts by weight of 1,4-butanediol, 1.92 parts by weight of a tetrabutyl-n-titanate solution prepared to a concentration of 3% by weight with 4-butanediol was added, and the system was placed in a nitrogen atmosphere by nitrogen-reduced pressure substitution. While stirring the system, the temperature was raised to 230 ° C. over 1 hour, and the reaction was carried out at this temperature for 2 hours and 30 minutes. When the terminal acid value of the obtained ester oligomer was measured, it was 303 eq. / Ton.
To this ester oligomer, 4.2 parts by weight of a 1,4-butanediol solution prepared so as to have an ethyl acid phosphate concentration of 2.7% by weight and a magnesium acetate concentration of 1.1% by weight was added.

  Next, while stirring the system at 150 rpm, the temperature was raised to 250 ° C. over 30 minutes, and the pressure was reduced to 70 Pa at the same time, and the stirring rotation speed of the stirring device after the pressure reduction was lowered stepwise to 150 rpm, 60 rpm, 40 rpm, and 20 rpm. It was. When the torque value reached 0.2 N · m at 20 rpm, the contents were extracted as a strand from the bottom of the reaction vessel at 230 ° C. and submerged in 10 ° C. water, and then the strand was cut with a cutter. White pellets were obtained by heating and drying at 60 ° C. for 8 hours under vacuum.

  The resulting pellet has a yellowness (YI) of 0 and a terminal acid value of 45 eq. / Ton, the intrinsic viscosity was 1.32 dL / g.

[Comparative Example 1]
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a vacuum outlet, 100 parts by weight of adipic acid, 101 parts by weight of terephthalic acid, 174 parts by weight of 1,4-butanediol, Then, 3.21 parts by weight of tetrabutyl-n-titanate solution prepared to a concentration of 3% by weight with 4-butanediol was added, and the inside of the system was put into a nitrogen atmosphere by nitrogen-vacuum substitution. While stirring the system, the temperature was raised to 230 ° C. over 1 hour, and the reaction was carried out at this temperature for 5 hours. When the terminal acid value of the obtained ester oligomer was measured, it was 26 eq. / Ton.

  To the ester oligomer, 2.93 parts by weight of a 1,4-butanediol solution prepared so as to have an ethyl acid phosphate concentration of 0.4% by weight and a magnesium acetate concentration of 0.6% by weight was added.

  Next, while stirring the system at 150 rpm, the temperature was raised to 250 ° C. over 30 minutes, and the pressure was reduced to 70 Pa at the same time, and the stirring rotation speed of the stirring device after the pressure reduction was lowered stepwise to 150 rpm, 60 rpm, 40 rpm, and 20 rpm. It was. When the torque value reached 0.2 N · m at 20 rpm, the contents were extracted as a strand from the bottom of the reaction vessel at 230 ° C. and submerged in 10 ° C. water, and then the strand was cut with a cutter. Pink pellets were obtained by heating and drying at 60 ° C. for 2 hours under vacuum.

  The obtained pellet had a yellowness (YI) of 64 and a terminal acid value of 14 eq. / Ton, the intrinsic viscosity was 1.39 dL / g.

[Example 3]
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a vacuum outlet, 100 parts by weight of adipic acid, 101 parts by weight of terephthalic acid, 203 parts by weight of 1,4-butanediol, 1, 1.60 parts by weight of a tetrabutyl-n-titanate solution prepared to a concentration of 3% by weight with 4-butanediol was added, and the inside of the system was put into a nitrogen atmosphere by nitrogen-reduced pressure substitution. While stirring the system, the temperature was raised to 230 ° C. over 1 hour, and the reaction was carried out at this temperature for 2 hours and 30 minutes. When the terminal acid value of the obtained ester oligomer was measured, 376 eq. / Ton. The amount of distillate in this esterification was 62.3 parts by weight, and the tetrahydrofuran concentration obtained by the absolute calibration method of gas chromatography was 9.1% by weight. From this, the by-product amount of tetrahydrofuran was 5.7 parts by weight.

  To this ester oligomer, 3.7 parts by weight of a 1,4-butanediol solution prepared to have an ethyl acid phosphate concentration of 0.9% by weight and a magnesium acetate concentration of 1.1% by weight was added.

  Next, while stirring the system at 150 rpm, the temperature was raised to 250 ° C. over 30 minutes, and the pressure was reduced to 70 Pa at the same time, and the stirring rotation speed of the stirring device after the pressure reduction was lowered stepwise to 150 rpm, 60 rpm, 40 rpm, and 20 rpm. It was. When the torque value reached 0.2 N · m at 20 rpm, the contents were extracted as a strand from the bottom of the reaction vessel at 230 ° C. and submerged in 10 ° C. water, and then the strand was cut with a cutter. By heating and drying at 60 ° C. for 8 hours under vacuum, 271 parts by weight of white pellets were obtained.

  The resulting pellet had a yellowness (YI) of -6 and a terminal acid value of 42 eq. / Ton, the intrinsic viscosity was 1.41 dL / g. 2.1 parts by weight of tetrahydrofuran was by-produced per 100 parts by weight of the pellets.

[Comparative Example 2]
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a vacuum outlet, 100 parts by weight of adipic acid, 101 parts by weight of terephthalic acid, 203 parts by weight of 1,4-butanediol, 1, 3.19 parts by weight of a tetrabutyl-n-titanate solution prepared to a concentration of 3% by weight with 4-butanediol and 5.9% by weight of an ethyl acid phosphate solution prepared to a concentration of 1% by weight with 1,4-butanediol. The system was put into a nitrogen atmosphere by nitrogen-vacuum substitution. The terminal acid value upon addition of this phosphorus compound is theoretically 9559 eq. / Ton. While stirring the system, the temperature was raised to 230 ° C. over 1 hour, and the reaction was carried out at this temperature for 2 hours and 30 minutes. When the terminal acid value of the obtained ester oligomer was measured, it was 554 eq. / Ton. The amount of distillate in this esterification was 70.5 parts by weight, and the tetrahydrofuran concentration obtained by the absolute calibration method of gas chromatography was 31%. From this, the by-product amount of tetrahydrofuran was 21.8 parts by weight. Thereafter, 0.73 parts by weight of a 1,4-butanediol solution prepared to have a magnesium acetate concentration of 10% by weight was added.

  Next, while stirring the system at 150 rpm, the temperature was raised to 250 ° C. over 30 minutes, and the pressure was reduced to 70 Pa at the same time, and the stirring rotation speed of the stirring device after the pressure reduction was lowered stepwise to 150 rpm, 60 rpm, 40 rpm, and 20 rpm. It was. When the torque value reached 0.2 N · m at 20 rpm, the contents were extracted as a strand from the bottom of the reaction vessel at 230 ° C. and submerged in 10 ° C. water, and then the strand was cut with a cutter. By heating and drying at 60 ° C. for 8 hours under vacuum, 271 parts by weight of white pellets were obtained.

The resulting pellet has a yellowness (YI) of 4 and a terminal acid value of 37 eq. / Ton, the intrinsic viscosity was 1.37 dL / g. 8.0 parts by weight of tetrahydrofuran was by-produced per 100 parts by weight of the pellets.
The reaction conditions and reaction results of Examples 1 to 3 and Comparative Examples 1 and 2 are summarized in Table 1.

In addition, each item in Table 1 shows the following values.
Ti (ppm): Ti equivalent addition amount of titanium compound to polymer (weight ppm)
P (mol / mol-Ti): P compound addition molar amount ratio of phosphorus compound to Ti conversion addition molar amount of titanium compound 1,4-BG / acid (mol / mol): 1, to all dicarboxylic acids subjected to the reaction Molar ratio of 4-butanediol Terminal acid value (eq./ton): Terminal acid value of the ester oligomer obtained in the esterification reaction step (Comparative Example 2 is an in-system terminal acid value when a phosphorus compound is added), or The terminal acid value of the polyester obtained in the polycondensation reaction step Mg (mol / mol-Ti): ratio of the magnesium compound added molar amount of the magnesium compound to the Ti converted added molar amount of the titanium compound YI: yellowness of the obtained polyester (YI)
Intrinsic viscosity (dL / g): Intrinsic viscosity of the obtained polyester THF (g / 100 g-PBAT): tetrahydrofuran production amount (g) with respect to 100 g of the produced polyester

From Table 1, it can be seen that according to the present invention, it is possible to efficiently obtain a high-quality aliphatic aromatic polyester having good color tone by suppressing the by-production of tetrahydrofuran.
On the other hand, the terminal acid value of the ester oligomer is 30 eq. In Comparative Example 1 less than / ton, YI is high, and a polyester having a good color tone cannot be obtained.
Moreover, in Comparative Example 2 in which the phosphorus compound was added in the esterification reaction step, the amount of tetrahydrofuran by-product was large and inefficient.

  By the production method of the present invention, by-product formation of tetrahydrofuran can be suppressed, and a high-quality aliphatic aromatic polyester having a good color tone can be efficiently obtained, and a commercial value is high using this aliphatic aromatic polyester. A molded article can be provided.

DESCRIPTION OF SYMBOLS 1 Raw material supply line 2 Recirculation line 3 Catalyst supply line 4 Ester oligomer extraction line 5 Distillation line 6 Extraction line 7 Circulation line 8 Extraction line 9 Gas extraction line 10 Condensate line 11 Extraction line 12 Circulation line 13 Extraction line 14 Vent line A Esterification reaction tank B Extraction pump C Rectification tower D Pump E Pump F Tank G Condenser L1, L3, L5 Polycondensation reaction product extraction line L2, L4, L6 Vent line L7 Catalyst supply Line L8 Raw material supply line a 1st polycondensation reaction tank d 2nd polycondensation reaction tank k 3rd polycondensation reaction tank c, e, m Gear pump for extraction h Underwater cutter n Filter

Claims (3)

An ester oligomer is obtained by esterifying and / or transesterifying an aliphatic diol component, an aliphatic dicarboxylic acid component, and an aromatic dicarboxylic acid component in the presence of a catalyst, and the ester oligomer is supplied to a polycondensation reaction step. In a method for producing an aliphatic aromatic polyester by performing a polycondensation reaction,
The terminal acid value of the ester oligomer is 30 to 1000 eq. / Ton,
A method for producing an aliphatic aromatic polyester, wherein the ester oligomer is brought into contact with a phosphorus compound before the ester oligomer is supplied to the polycondensation reaction step.   The method for producing an aliphatic aromatic polyester according to claim 1, wherein an alkaline earth metal compound is brought into contact with the ester oligomer together with the phosphorus compound.   The method for producing an aliphatic aromatic polyester according to claim 2, wherein the alkaline earth metal compound is a magnesium compound.

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